2012 June 02 Saturday
Andromeda And Milky Way To Collide In 4 Billion Years

The Hubble Space Telescope keeps on giving. Brace for impact.

The Milky Way is set to collide with its closest neighbor, the Andromeda galaxy, astronomers working with the Hubble Space Telescope said Thursday. Galactic residents need not brace for impact just yet, however: The predicted collision would take place in 4 billion years.

So imagine you live long enough to still be around when rejuvenation therapies become available. Will any rejuvenated people from the 20th or 21st century survive millions of years? Billions of years? One would have to be both very risk avoidant and very lucky to make it that long. Plus,one would need to travel in a planet spaceship between stars when Sol gets too old. How far would humanity need to travel to get to a much younger star?

During the 2 billion year collision periodour sun will be thrown further away from the galactic core.

Computer simulations derived from Hubble's data show that it will take an additional two billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe.

Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.

I want to know whether aliens from Andromeda will use the collision as an opportunity to invade the Milky Way.

By Randall Parker    2012 June 02 09:15 PM   Entry Permalink | Comments (15)
2012 March 21 Wednesday
Elon Musk: Half Million Dollar Mars Round Trip?

Can Musk be serious?

Rocket entrepreneur Elon Musk believes he can get the cost of a round trip to Mars down to about half a million dollars.

I am skeptical.

Think of it from the perspective of energy costs. Not only does the energy have to be expended to move your body to Mars and back. But also all your food and energy, oxygen recycling, drugs, and assorted supplies have to be carried there with you. That all takes many more times energy.

Here's what I want to know: How to calculate the energy costs of a human trip to Mars? How much mass has to be moved per person? Just in supplies how much has to be sent to Mars for, say, a 180 lb person? 20 times their weight? 50 times? Then there is the fuel and the spacecraft. What's the total mass ratio of everything else per pound (or kg) of person.

Musk thinks he can get the cost of lifting weight into space below $1000 per lb. But suppose he gets it to $500 per lb. A half million dollars still only pays to lift 1000 lbs into Earth orbit. Most of that mass will be used to lift other mass to Mars (mostly fuel burned to move other fuel). He acknowledges the need for a 2 orders of magnitude cost reduction. I'm skeptical he's going to succeed at that in the next 10 years.

Space travel comes down the cost of moving mass around. We need orders of magnitude cheaper costs of getting stuff into orbit and then moving stuff out of Earth orbit and then into Mars orbit.

By Randall Parker    2012 March 21 10:02 PM   Entry Permalink | Comments (8)
2011 August 24 Wednesday
Travel Between Stars?

As long as we do not have warp drives will it ever be worth it for humans to travel to other stars and back again? A New York Times article on a Defense Advanced Research Projects Agency (DARPA) grant to study what it would take for humans to travel between the stars makes an interesting claim: travel between the stars would take so long that whoever went out would not return.

An actual human launching is at least a couple of centuries away and, barring the invention of Star Trek-like warp drives, could take additional centuries to complete. Whoever goes on such a journey will not be coming back.

The idea is that either a robot carries back findings or the descendants of the original travelers come back to a planet they've never seen before.

I have a problem with this line of reasoning. First off, the time to travel between stars is so long that anyone who is going to age normally won't even live to see their destination, let alone return to Earth. So why go in the first place? So your grandchildren or great grandchildren can stand on another planet?

Since a destination planet would very likely not have an ecosphere compatible with human life what would be the point even for those descendants still alive when the space ship (perhaps a hollowed-out asteroid) reached the destination? If the destination has life there's a decent chance its microbes will kill humans. So why go?

But why go into space with a body that ages? It would seem far more sensible to wait until humans develop bio-technologies needed to stay young for thousands of years. Then one could travel to another start and get back again even if the trip took hundreds or even thousands of years.

Of course, even if you can stay alive the whole time the longer the trip the less the point to it. Unless you can pass hundreds of years in cryogenic sleep why box yourself into a relatively small habitat to travel for hundreds of years? It would seem extremely boring and a waste of years better spent on more rewarding activities. Be bored for hundreds of years go get to some planet to stay for some years before turning around to head back again? The reward/boredom ratio seems extremely low. Plus, there's the risk you'll die.

Perhaps with genetic engineering humans could be designed who'd find the trip thrilling. Or cryogenic sleep might provide a way to escape the boredom of centuries of travel.

A lot can happen on Earth while you travel between the stars. Imagine you travel for centuries, get to your destination, and a warp drive space ship from Earth is there waiting for you and it just left Earth 5 days previously. What a waste that would be.

By Randall Parker    2011 August 24 10:56 PM   Entry Permalink | Comments (21)
2010 May 15 Saturday
Weightlessness Messes Up Immune Genes?

Weightlessness (or higher background radiation) in space messed up genes that control stress and immune response. Yet another example of how we need to be able to genetically reengineer ourselves in order to move off-planet. We evolved on this planet and are adapted to a pretty narrow range of conditions.

Tucson, Ariz. -- Astronauts are known to have a higher risk of getting sick compared to their Earth-bound peers. The stresses that go with weightlessness, confined crew quarters, being away from family and friends and a busy work schedule - all the while not getting enough sleep - are known to wreak havoc on the immune system.

A research group led by immunobiologist Ty Lebsack at the University of Arizona has discovered that spaceflight changes the activity of genes controlling immune and stress response, perhaps leading to more sickness.

Shooting humans up into space on current generation (or even next generation) chemical rockets is just a show. It accomplishes extremely little. That we even do it demonstrates the excessively high discount rate of most humans. Said discount rate a product of an evolutionary past which required much more shorter term planning than today). If we really wanted to go move off world we would need to spend decades developing a wide range of really advanced technologies needed to make the move. We need nanotech, genetic engineering of food and fiber crops, genetic engineering of plants organisms that would clean our environment. robots, AI, and fusion energy for starters.

Just 13 days riding on the (obsolete and bad design) Space Shuttle was enough to wack out gene expression in mouse thymus tissue.

Lebsack and his colleagues focused their study on the thymus gland, the organ that serves as a "factory" and "training academy" for T-cells that are key players of the immune system. They compared gene-expression patterns in thymuses from four healthy mice that had spent 13 days aboard NASA's STS-118 Endeavor Space Shuttle to those from an equal number of control mice on the ground.

Their finding: 970 individual genes in the thymus of space-flown mice were up or down-regulated by a 1.5 fold change or greater. When these changes were averaged, 12 genes in the thymus tissue of all four space-flown mice were significantly up or down-regulated. "The altered genes we observed were found to primarily affect signaling molecules that play roles in programmed cell death and regulate how the body responds to stress," Lebsack said.

We also need genetic engineering for maintaining bone mass, muscle mass, and joint mass among other things. The higher level of radition we'd experience on a trip to Mars argues for waiting for cures for cancer before trying to colonize Mars.

By Randall Parker    2010 May 15 04:34 PM   Entry Permalink | Comments (2)
2010 May 12 Wednesday
NASA Seen Spending Too Little On Science

the National Academy of Sciences' National Research Council says NASA's budget is weighted too far toward human space flight and not enough toward basic research.

WASHINGTON — The decline of basic research at the National Aeronautics and Space Administration jeopardizes the agency’s ability to study and explore the cosmos, a review panel of scientists and engineers said Tuesday.

The findings could bolster the arguments of the Obama administration that NASA’s current effort to send astronauts back to the Moon is too expensive and is siphoning too much money from other programs. The president’s $19 billion budget for NASA in the 2011 fiscal year would cancel the Moon program, known as Constellation, and replace it with the development of technologies intended to achieve a cheaper, more sustainable approach for sending people into space.

My take: Human space flight competes with science for money. Human space flight is done to give people a show (not that many people even watch). It is done so that Americans can say "See, we have people in space". It doesn't accomplish much per dollar spent. Robotic vehicles can explore many more places for a fraction of the price.

What we need: much cheaper ways to get into space and move around while there. Humans aren't going to do much in space as long as getting there costs hundreds of millions of dollars per launch. Incremental new designs of chemical rockets won't chagne that picture. We need advances in materials (e.g. to build a nanotube bean stalk elevator into space) that will enable development of much better ways of getting up there and moving around once there.

To go into space in substantial numbers we need far cheaper and safer ways to get into orbit, ways to propel spaceships between planets much more rapidly (to avoid humans getting fried by radiation in transit), and advances in biotechnology to adapt humans to zero gravity and to enable the growing of food, fiber, and drugs on moona and Mars colonies. Money spent on visits to the International Space Station does not address these needs.

By Randall Parker    2010 May 12 12:39 AM   Entry Permalink | Comments (11)
2010 March 25 Thursday
Universe Still Expanding

The universe is still hurdling toward oblivion.

University of British Columbia astronomer Ludovic Van Waerbeke with an international team has confirmed that the expansion of the universe is accelerating after looking at data from the largest-ever survey conducted by the Hubble Space Telescope.

The astronomers studied more than 446,000 galaxies to map the matter distribution and the expansion history of the universe. This study enabled them to observe precisely how dark matter evolved in the universe and to reconstruct a three-dimensional map of the dark matter and use this to test Albert Einstein's theory of general relativity.

I find the idea of an accelerating universe depressing. Is the universe going to gradually spread out until each atom is by itself? Does the universe sort of end by diffusion where its various parts effectively become disconnected?

The researchers looked at 446 thousand galaxies. Imagine the number of stars in those galaxies.

A group of astronomers [1], led by Tim Schrabback of the Leiden Observatory, conducted an intensive study of over 446 000 galaxies within the COSMOS field, the result of the largest survey ever conducted with Hubble. In making the COSMOS survey, Hubble photographed 575 slightly overlapping views of the same part of the Universe using the Advanced Camera for Surveys (ACS) onboard Hubble. It took nearly 1000 hours of observations.

Just how many intelligent species have developed in these many galaxies? How many of those species got wiped out by supernovas, colliding stars, colliding galaxies, black holes, or quasars? What fraction of all the intelligent species that ever existed still exist today? How many are effectively unreachable?

By Randall Parker    2010 March 25 10:28 PM   Entry Permalink | Comments (14)
2009 December 14 Monday
Super-Earths Found Orbiting Nearby Stars

Rocky planets as small as 5 times Earth's mass have been found orbiting stars in our neighborhood. These results suggest we will find a lot more solar systems with planets closer to our own in size. Have intelligent dinosaurs developed on some and do they see us hominids as revolting enemies? Or as tasty snacks?

Washington, D.C. — Two nearby stars have been found to harbor "super-Earths"― rocky planets larger than the Earth but smaller than ice giants such as Uranus and Neptune. Unlike previously discovered stars with super-Earths, both of the stars are similar to the Sun, suggesting to scientists that low-mass planets may be common around nearby stars.

"Over the last 12 years or so nearly 400 planets have been found, and the vast majority of them have been very large―Jupiter mass or even larger," says researcher Paul Butler of the Carnegie Institution's Department of Terrestrial Magnetism. "These latest planets are part of a new trend of finding much smaller planets – planets that are more comparable to Earth."

The international team of researchers, co-led by Butler and Steven Vogt of the University of California, Santa Cruz, was able to detect the new planetary systems by combining data from observations spanning several years at the W. M. Keck Observatory in Hawaii and the Anglo-Australian Telescope in New South Wales, Australia. The researchers used the subtle "wobbling" of the stars caused by the planets' gravitational pull to determine the planets' size and orbits. Greg Henry at Tennessee State University independently monitored the brightness of the stars to rule out stellar "jitter"―roiling of gases on a star's surface that can be confused with a planet-induced wobble.

The bright star 61 Virginis, visible with the naked eye in the constellation Virgo, is only 28 light-years from Earth and closely resembles the Sun in size, age and other properties. Earlier studies had eliminated the possibility of a Jupiter-sized planet orbiting 61 Virginis. In this study, the researchers found evidence of three low-mass planets, the smallest of which is five times the mass of Earth and speeds around the star once every four days.

Will some of us live long enough to find life on other planets? Is it possible to detect life on a planet in another solar system without picking up radio signals?

Think of the possibilities. We could ask older civilizations if they overheated their planets by burning fossil fuels.

"These planets are particularly exciting," said team member Professor Chris Tinney of the University of NSW. "Neptune in our Solar System has a mass 17 times that of the Earth. It looks like there may be many Sun-like stars nearby with planets of that mass or less. They point the way to even smaller planets that could be rocky and suitable for life."

By Randall Parker    2009 December 14 10:04 PM   Entry Permalink | Comments (1)
2009 November 24 Tuesday
Space Exploration Takes Too Long For Democracies?

Will China's lack of democracy give it a leg up in the next wave of human space exploration? Michael Hanlon argues the next big step in space exploration takes too much time for a democracy to fund it.

It may simply be that space exploration is incompatible with US democracy. A Mars shot would take four presidential terms at least. No president will ask taxpayers to fund something he won't be around to take credit for.

He's probably right given the way we've approached space exploration to date. As long as we approach space exploration as something to do with small incremental improvements in technology we are going to spend vast sums for stunts of little lasting significance (e.g. the Apollo program to the Moon). I question the utility of spending 16 years and large sums of money to go to Mars for a brief human visit.

I think in terms of enabling the next big step in human colonization. Why go if you can't stay? We really need to develop far cheaper technologies for space launch and space travel. Spending big money to develop conservatively designed rockets for a Mars trip does not develop the level of technology we need to move enough stuff and safely move enough people to Mars to set up a permanent colony.

The Apollo program and moon shots should teach us that getting to some place at high cost per trip and without staying power ends up turning into a short term stunt that leaves no enduring presence off-planet. Great video. Some cool rocks. But then no further action for decades.

The space shuttle and space station are boring and not accomplishing much.

Another big problem is the legacy of some terrible decisions that left NASA with the expensive, dangerous space shuttle and a white-elephant space station that manages the feat of making space seem as dull as cardboard. The whole thing is a mess.

The space shuttle is old technology and highly cost ineffective. Funding it has provided video footage of people hurling into space. But it hasn't done anything to advance the state of the art for space launch for a very long time.

Funding the usage of old space technology is a waste that is done as a form of entertainment. The proposed Mars mission would use pretty conventional technology for space launch and for interplanetary travel. I see this as a waste of time. We need bigger steps forward that can lower costs and drastically cut risks. A space elevator made using nanotechnology could radically slash the cost of reaching low Earth orbit. To get to Mars a nuclear electric plasma propulsion system could transport humans in less than 6 weeks.

For humans to travel safely to Mars and beyond, it will be important to make the trip as quickly as possible and thereby reduce the crew's exposure to weightlessness and space radiation. With today's chemical rockets, a round-trip to Mars would take over two years, with much of that time spent waiting for the right planetary alignment to return. More rapid transits are possible with a VASIMR® propulsion system powered by a nuclear-electric generator. With 12 megawatts of electrical power, a ship could reach Mars in less than four months and with 200 megawatts of power the outbound trip could be as short as 39 days.

Our first priority for space exploration should be the development of technologies that make a human presence off-planet sustainable and low risk. Fast cheap safe transportation is a key piece of the puzzle.

By Randall Parker    2009 November 24 06:57 PM   Entry Permalink | Comments (26)
2009 October 28 Wednesday
Higher Estimate For Number Of Parallel Universes

But can we ever get to them?

HOW many universes are there? Cosmologists Andrei Linde and Vitaly Vanchurin at Stanford University in California calculate that the number dwarfs the 10500 universes postulated in string theory, and raise the provocative notion that the answer may depend on the human brain.

I want to travel between universes far more than I want to travel between stars in this universe. What I'd really like to find: Universes that causally split off from this universe hundreds or thousands of years ago. How did history turn out if a small event caused different decisions 300 years ago? Different people would be born. Accidents would play out differently.

Splitting universes causally much further back would lead to evolution of different species. Might parallel Earths without highly intelligent animals exist? Might such an Earth have lots of species that were driven extinct by humans in this universe? Such a universe would help to settle climate debate questions. Without humans did the Earth fall back into another Ice Age?

By Randall Parker    2009 October 28 11:12 PM   Entry Permalink | Comments (13)
2009 September 16 Wednesday
Too Much Radiation For Humans In Mars Trip

Dreams of a human trip to Mars run up against limits to allowable human radiation exposure.

But calculations by Cucinotta and his colleagues suggest the trip would not meet NASA's existing rules, which aim to keep each astronaut's lifetime risk of fatal cancer from space radiation below 3 per cent.

For journeys outside Earth's magnetic field, astronauts could reach that limit in less than 200 days in a spacecraft with aluminium walls nearly 4 centimetres thick, according to worst-case scenario estimates (Radiation Measurements, DOI: 10.1016/j.radmeas.2006.03.011).

But a trip to Mars and back would take over 2 years. Two potential solutions:

  • Travel much faster.
  • Use several times the amount of mass as would otherwise be used.

Of course both of these approaches require far more energy. The faster trip is especially problematic because more energy would be available to launch a space ship toward Mars than to launch it back toward Earth. Getting a ship to move fast enough on the return trip would be a big challenge.

One way to get a ship to Mars that would have lots of chemical rocket mass to propel a return trip: Send two space ships. First send one slowly that would carry a lot of fuel. That fuel would enter Mars orbit before humans even left Earth. Then humans could leave Earth on a fast ship and arrive to find another fast ship with lots of fuel ready to take them back to Earth.

Part of the radiation exposure would come while humans are on Mars. How to reduce that exposure? Send robots ahead of time that would burrow down underground to create living quarters in several places that would be within driving distance of each other. The astronauts could move from underground shelter to underground shelter.

Of course, all this requires huge amounts of money and resources. Could other approaches work? I can imagine beam technology for pushing spaceships to faster speeds with power sources on stations in orbit around Earth and Mars.

What else? Think small. Methods to cure cancer or prevent cancer would reduce the scale of the problem. Nanobots could repair astronaut bodies as the damage occurred. Or nanobots could kill cancer. So we can wait 30-40 years to go to Mars until we have the biotechnology and nanotechnology sufficient to reduce the risks from higher radiation exposure.

I do not see the point of going to Mars with today's technology. Better to first push the edge of what is possible before sending humans on a trip that would put people on another planet for a pretty limited period of time. Humans went to the moon all we got were some cool videos.

By Randall Parker    2009 September 16 10:12 PM   Entry Permalink | Comments (20)
2009 July 30 Thursday
Where Are The Alien Space Probes?

Carlos Cotta and Álvaro Morales of the University of Malaga take a slightly novel approach to the question of "where the heck are the space aliens anyhow?". If intelligent life evolved elsewhere it should have happened far enough back in time that these aliens would have spread out over much of the galaxy by now. Cotta and Morales says that since alien space probes can spread out much faster than alien colonists we should look for the space probes first and their absence even further decreases the odds of intelligent alien life elsewhere.

The numbers that Cotta and Morales come up with depend crucially on the life span of the probes doing the exploring (and obviously on the number of probes each civilization sends out). They say that if each probe has a life span of 50 million years, and if evidence of their solar-system visits lasts about a million years, there can be no more than about 1,000 advanced civilizations out there now. If, instead, these probes can leave longer-lasting evidence of a visit--evidence that remains for 100 million years--then there can be no more than about 10 civilizations out there.

Well, they've got to make a lot of assumptions in their model to come to these conclusions. I think the most questionable assumption is that of long-lasting evidence of a space probe visit. I've been reading Alan Weisman's very entertaining The World Without Us about how quickly lots of our buildings and other artifacts would crumble in our absence. If billions of humans make things that last for such short periods of time why should we expect a space probe to leave signs that would last 100 million years? Also, what can we expect such a probe to do to leave a signature for us to find?

Now, maybe the space probes have left evidence. But maybe the evidence is in a form that requires us to become much more advanced before we can detect it. Maybe 50 years from robots on Mars will dig up a monolith left by a space probe. Or maybe a space probe left behind a smaller watching probe that is in an orbit further out in our solar system listening for signs of more intelligent life.

If a probe contained nanobots that allowed it to build up new probes at each planet then I would expect a much faster spread of probes. Each probe could reach a suitable solar system and just start producing more probes. Then machine civilization would take over the galaxy.

Here's the abstract.

Update: When it comes to alien space exploration the key question you have to ask is "what is their motive?". Are they out there looking for species to conquer and destroy or enslave for sport? Do they think all other species are a threat and need to be eliminated? Are they looking for planets to colonize? Or are they looking for other species out of curiosity? Depending on motive the space probes will have different capabilities and missions.

If the motive of aliens is defensive then an artificial intelligence might be sitting out in the asteroid belt monitoring Earth for a hundred million years watching for signs of intelligence. The AI might have algorithms for rating intelligences by aggressivity and hostility. It might have a means to sterilize this planet if it decides we are a threat. Such an AI would not have been sent to leave a clear record of its presence.

So what motivates other intelligent species? That's the key question.

By Randall Parker    2009 July 30 11:22 PM   Entry Permalink | Comments (39)
2009 April 03 Friday
Warp Drive Destabilizes At Light Speed

Captain, the warp drive is destabilizing.

Bad news I'm afraid -- it looks as if faster-than-light travel isn't possible after all. That's the conclusion of a new study into how warp drives would behave when quantum mechanics is taken into account. "Warp drives would become rapidly unstable once superluminal speeds are reached," say Stefano Finazzi at the International School for Advanced Studies in Trieste, Italy, and a couple of friends.

The details.

I'm more interested in visiting parallel universes. Parallel Earths of universes that diverged from our timeline within tens or even hundreds of millions of years are more likely to be compatible with human life than other planets in our universe where life separately evolved.

By Randall Parker    2009 April 03 11:14 PM   Entry Permalink | Comments (7)
2009 March 22 Sunday
Technique Might Cut Bone Loss In Zero Gravity

We humans aren't adapted to the zero gravity conditions of orbit or the lower gravity conditions of the Moon and Mars. This poses a problem for efforts to establish permanent colonies off of planet Earth. Astronauts lose a lot of bone mass in zero gravity. But some scientist have found a way to reduce bone loss in zero G.

Bone loss in long-duration spaceflight has been identified for decades as a significant problem affecting astronauts. More recently, scientists have found that the absence of gravity is causing astronauts on the International Space Station to lose up to 10 times more bone mass in key regions of the body each month than most post-menopausal women do in the same period of time back here on Earth.

Now, by simulating spaceflight conditions through the use of long-duration bedrest, researchers at the University of Washington have found -- for the first time -- a way to prevent bone loss in a specific region of the hip. Using bedrest as an analog of spaceflight, UW scientists are at the mid-point of a study in which 22 volunteers remain in bed, in a six-degree, head-down tilt position for 84 days.

The trick sounds pretty simple: a harness pulls them toward a treadmill while they walk and run on it.

The head-down tilt mimics many of the physiologic adaptations astronauts experience during spaceflight, such as bodily fluid shifts toward the head. The bedrest confinement mimics the complete "unloading" of the musculoskeletal system that astronauts feel as they float through space due to the lack of gravity, which accelerates bone loss. Half of the study participants are randomized to perform individually prescribed intermittent treadmill exercise similar to workouts by astronauts in space -- but with one important difference: they are pulled towards the treadmill surface by a harness applying greater force than what the research team has previously measured during walking and running on the International Space Station treadmill.

"We have found that we can, on average, prevent bone loss in an important region of the hip with this intervention," said Dr. Peter Cavanagh, UW professor of orthopaedics and sports medicine, and principal investigator of the study. "No bedrest study ever before has accomplished this."

This technique probably isn't going to replace the effects of gravity in every bone. But it is a step forward.

To solve this problem well enough to allow long term living in lower gravity environments like Mars requires changes to human physiology. We probably need genetic engineering to enhance the response of bones to stresses. When in lower gravity environments lower amounts of stress should cause as much bone building as higher amounts cause here on Earth.

By Randall Parker    2009 March 22 11:35 PM   Entry Permalink | Comments (3)
2009 March 18 Wednesday
A Hypothesis About Our Universe

Our universe is some other universe's idea of a novel. Our universe is a simulation that allows the readers from another universe to fully immerse themselves in detailed plot lines all over this simulated universe.

By Randall Parker    2009 March 18 10:16 PM   Entry Permalink | Comments (19)
2009 March 09 Monday
Concentrating Solar Power Needed For Moon Base

Nukes weigh too much to transport to the Moon for a extended living lunar base. Yet the nights get extremely cold. The US government wants to return to the Moon in 2020. What to do? Concentrating solar power could heat up bricks made from Moon soil and used as heat sources during long periods of darkness.

This has led some engineers to explore a live-off-the-regolith approach – taking advantage of the positive side of lunar dust: It stores heat.

Specifically, the top four inches of the regolith absorbs sunlight and heats up. Lunar explorers could harvest this material and fashion it into large bricks. Using special lenses, they could intensify the sunlight striking the bricks, heating them to temperatures far higher than they could reach with sunlight alone. Then the heated bricks could be kept insulated and used for heating habitats during the long night.

But habitats aren’t the only pieces of hardware that must be warmed. Robotic rovers and their batteries also need to survive. “We have a hard time keeping … trucks working in Siberia,” Dr. Ramachandran says. “We have no experience working at minus 150 degrees.”

The article discusses the use of reflectors on an even bigger scale to heat up areas of lunar surface where equipment would be stored. Then once night came an area would be covered with a material that reflects infrared back down toward the parked equipment.

It makes sense to wait for 10 years since by then we'll have better solar concentrators and much better batteries for storing electric power from higher efficiency solar photovoltaics panels.

Wind power has no future on the Moon.

By Randall Parker    2009 March 09 09:12 PM   Entry Permalink | Comments (6)
2009 January 15 Thursday
Methane On Mars Might Indicate Lifeforms

I hear Gene Wilder yelling "Its alive! Its alive! Its alive!". Methane on Mars might be a sign of biological activity below the surface. (same here)

WASHINGTON -- A team of NASA and university scientists has achieved the first definitive detection of methane in the atmosphere of Mars. This discovery indicates the planet is either biologically or geologically active.

It would be so much better if the methane is biological, not geological. Then we'd need to create some sort of automated instrument (probably involving microfluidic devices) that could analyze biological material on Mars to look for DNA and similar compounds. Do Martian bacteria use the same letters of the genetic alphabet that we are made out of? Could be. A Martian rock might have brought life to Earth - or perhaps vice versa.

The team found methane in the Martian atmosphere by carefully observing the planet throughout several Mars years with NASA's Infrared Telescope Facility and the W.M. Keck telescope, both at Mauna Kea, Hawaii. The team used spectrometers on the telescopes to spread the light into its component colors, as a prism separates white light into a rainbow. The team detected three spectral features called absorption lines that together are a definitive signature of methane.

"Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas," said Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Md. "At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif." Mumma is lead author of a paper describing this research that will appear in Science Express on Thursday.

The organisms that amazingly live over a mile underground on Earth illustrate the possibility that ancient life forms on Mars could have survived long after the surface became inhospitable.

"On Earth, microorganisms thrive about 1.2 to 1.9 miles beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen and oxygen," Mumma said. "The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon. Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons."

Of course, if all the living organisms on Mars are deep underground we are going to have a hard time reaching them with automated probes.

By Randall Parker    2009 January 15 11:47 PM   Entry Permalink | Comments (7)
2008 December 24 Wednesday
Space Station Cargo Delivery Still Expensive

Orbital Sciences Corp has won a $1.9 billion contract to carry 20 metric tons of cargo to the International Space Station in 8 flights. Think about those numbers. That's $95 million per metric ton to move cargo from ground level to low orbit. Those deliveries start in 2011 and run through 2015. A metric ton is 1000 kilograms or 2204.6 lbs. So the cost of putting stuff into low Earth orbit in 2015 is still going to be around $43k per lb or $95k per kg. At these prices large scale human colonization of space still seems a very distant prospect.

Those costs will come down a lot if a beanstalk into space built using nanotubes becomes possible. A bigger cost reduction for a Mars mission will come from nanotech advances. A bunch of nanodevices that can transform Mars landscape and produce needed supplies for a colony would reduce the size of the payload needed for setting up an initial colony.

The idea of moving to Mars remains unattractive to me at least until it becomes possible to massively terraform the planet. Move massive amounts of oxygen and nitrogen from Titan and Triton and suddenly a Mars where we could walk around outside and breath its air becomes a lot more appealing.

Nanotech assemblers will be the enabling technology for large scale colonization because they will lower the cost of creating the spaceships needed for terraforming.

By Randall Parker    2008 December 24 01:26 PM   Entry Permalink | Comments (18)
2008 November 22 Saturday
Massive Mars Glaciers Tempting Target For Global Warming

Good news for future human settlement of Mars: a supply of water for Mars colonists will not be a problem.

AUSTIN, Texas—Vast Martian glaciers of water ice under protective blankets of rocky debris persist today at much lower latitudes than any ice previously identified on Mars, says new research using ground-penetrating radar on NASA's Mars Reconnaissance Orbiter.

Because water is one of the primary requirements for life as we know it, finding large new reservoirs of frozen water on Mars is an encouraging sign for scientists searching for life beyond Earth.

The concealed glaciers extend for tens of miles from edges of mountains or cliffs and are up to one-half mile thick. A layer of rocky debris covering the ice may have preserved the glaciers as remnants from an ice sheet covering middle latitudes during a past ice age.

"Altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that's not in the polar caps. Just one of the features we examined is three times larger than the city of Los Angeles, and up to one-half-mile thick, and there are many more," said John W. Holt of The University of Texas at Austin's Jackson School of Geosciences, lead author of a report on the radar observations in the Nov. 21 issue of the journal Science.

"In addition to their scientific value, they could be a source of water to support future exploration of Mars," said Holt.

So would it be better to melt all that ice? Some of the water would evaporate into the atmosphere providing Mars with a higher atmospheric pressure. But it is not clear to me that would help. The amount of radiation reaching the surface would probably still be so high that underground colonies would continue to make the most sense. If the water is kept frozen then colonies could be located around glaciers and only melt as much water as needed.

To make Mars a full outside-living planet where can the oxygen come from? The outer planets seem to have little oxygen. Can anyone point to abundant sources of oxygen in this solar system outside of the Earth? The Mars glaciers are mostly oxygen since water is made from 2 hydrogens and an oxygen. But I doubt enough oxygen is in that water to support a high atmospheric pressure.

Neptune's moon Triton seems like the best place to go (leaving aside energy costs and time) to get oxygen and nitrogen for a Mars atmosphere. We could remove Triton's surface and transport it to Mars for the nitrogen and oxygen.

As with Pluto, 55% of Triton's surface is covered with frozen nitrogen, with water ice comprising 15–35% and dry ice (frozen carbon dioxide) forming the remaining 10–20%.

But does anyone know how much mass of nitrogen and oxygen are on Triton as compared to how much would be needed to give Mars an atmospheric pressure similar to that of Earth?

Or does anyone have a good source for how else enough oxygen and nitrogen could be found to make the Mars atmosphere capable of supporting humans outside?

Update: James Bowery points me to a problematic report on why Mars lost its atmosphere in the first place. David Brain of UC Berkeley says irregular magnetic fields on Mars cause pieces of the Martian atmosphere to pinch off and get blown away by the solar wind.

Brain was scrolling through archival data from Global Surveyor's particles and fields sensors. "We have measurements from 25,000 orbits," he says. During one of those orbits, MGS passed through the top of a magnetic umbrella. Brain noticed that the umbrella's magnetic field had linked up with the magnetic field in the solar wind. Physicists call this "magnetic reconnection." What happened next is not 100% certain, but Global Surveyor's readings are consistent with the following scenario: "The joined fields wrapped themselves around a packet of gas at the top of the Martian atmosphere, forming a magnetic capsule a thousand kilometers wide with ionized air trapped inside," says Brain. "Solar wind pressure caused the capsule to 'pinch off' and it blew away, taking its cargo of air with it." Brain has since found a dozen more examples. The magnetic capsules or "plasmoids" tend to blow over the south pole of Mars, mainly because most of the umbrellas are located in Mars' southern hemisphere.

So how can we create a strong consistent magnetic field on Mars capable of retaining an atmosphere for a long time? Bring iron in from elsewhere in the solar system? If so, where?

By Randall Parker    2008 November 22 07:16 PM   Entry Permalink | Comments (9)
2008 November 04 Tuesday
Small Magnetosphere Could Protect Space Travelers

If you've put off scheduling a Mars trip due to the threat from solar particle events and other sources of radiation a portable magnetosphere might some day make a trip to Mars much safer.

The solar energetic particles, although just part of the 'cosmic rays' spectrum, are of greatest concern because they are the most likely to cause deadly radiation damage to the astronauts.

Large numbers of these energetic particles occur intermittently as "storms" with little warning and are already known to pose the greatest threat to man. Nature helps protect the Earth by having a giant "magnetic bubble" around the planet called the magnetosphere.

....Researchers at the Science and Technology Facilities Council's Rutherford Appleton Laboratory, the Universities of York, Strathclyde and IST Lisbon, have undertaken experiments, using know-how from 50 years of research into nuclear fusion, to show that it is possible for astronauts to shield their spacecrafts with a portable magnetosphere - scattering the highly charged, ionised particles of the solar wind and flares away from their space craft.

Computer simulations done by a team in Lisbon with scientists at Rutherford Appleton last year showed that theoretically a very much smaller "magnetic bubble" of only several hundred meters across would be enough to protect a spacecraft.

Now this has been confirmed in the laboratory in the UK using apparatus originally built to work on fusion. By recreating in miniature a tiny piece of the Solar Wind, scientists working in the laboratory were able to confirm that a small "hole" in the Solar Wind is all that would be needed to keep the astronauts safe on their journey to our nearest neighbours.

Dr. Ruth Bamford, one of the lead researchers at the Rutherford Appleton Laboratory, said, "These initial experiments have shown promise and that it may be possible to shield astronauts from deadly space weather".

It is hard to protect astronauts outside of Earth's orbit from galactic cosmic radiation and solar particle events.

Energetic protons are mainly produced during solar particle events, sporadic showers that usually coincide with maximum sunspot activity. More dangerous is galactic cosmic radiation (GCR), atomic nuclei produced during supernova explosions that travel at almost the speed of light. GCR arrives from all directions, and induces cancer as it hurtles through the body. On Earth, the planet's magnetic field and atmosphere combine to deter and block these particles. But shielding a spacecraft requires mass, and the mass of shielding that can practically be launched on a spaceship will only reduce GCR by 20% to 30%, says Frank Cucinotta, of NASA's Space Radiation Health Project at the Johnson Space Center.

We need better robot tech in order to colonize Mars. The robots could go first and do lots of work to create living quarters and enclosed farms before humans arrived. We also need better photovoltaics or workable fusion reactors for energy. Plus, we need lots of genetic engineering to create organisms to provide a variety of products for colonists. Most of this tech will get developed for other reasons. So colonization of Mars will become much easier with time.

By Randall Parker    2008 November 04 09:34 PM   Entry Permalink | Comments (2)
2008 September 09 Tuesday
Stephen Colbert Commits Space Fraud With His DNA

Stephen Colbert is pretending to save his DNA for use by aliens who might show up once humanity is extinct. This is fraud!

NEW YORK, September 8, 2008 -- Stephen Colbert continues to make late-night television space history. On “The Colbert Report” in May, he was the first host in late-night to interview an astronaut, Garrett Reisman, in space. Now, Colbert plans to save humanity when he has his DNA digitized and sent to the International Space Station (ISS) with famed game designer Richard Garriott.

“I am thrilled to have my DNA shot into space, as this brings me one step closer to my life-long dream of being the baby at the end of 2001," said Colbert.

“In the unlikely event that Earth and humanity are destroyed, mankind can be resurrected with Stephen Colbert’s DNA,” said Garriott. “Is there a better person for us to turn to for this high-level responsibility?”

In October, Garriott will travel to the ISS and deposit the “Immortality Drive,” a time capsule which will include human DNA and records of humanity’s greatest accomplishments. This collection of data including Colbert’s DNA and accomplishments, along with personal messages left by visitors at www.OperationImmortality.com, will serve as a remote offsite backup of the human race.

A recent news report on the need to move the ISS to avoid Russian satellite junk shows why the report above is a fraud perpetrated on a naive and unsuspecting pseudo-news watching public: The space station decays in orbit by 100 to 300 feet per day and once the human race goes extinct (and probably well before then) the space station will reenter Earth's atmosphere and burn up. Colbert's DNA sequence will burn up looking like a comet across the night sky.

In a status report, NASA said the course change was required because the space debris was predicted to come within about a mile (1.627 kilometers) of the station — bringing the risk of a collision above the threshold for a "debris avoidance maneuver."

Normally, such maneuvers involve raising the station's altitude, to compensate for the orbit's inexorable decay from air drag. Such decay lowers the orbit by 100 to 300 feet per day, and requires periodic engine firings by docked spacecraft or rockets installed on the station itself.

The ISS is in too low an orbit to stay up in space until space alien archaeologists show up to pick over the wreckage of our vanquished civilization. To preserve DNA sequences for eventual recreation of humans in an alien zoo would require use of either a geosynchronous high orbit or perhaps a pod on the Moon.

Update: If Colbert was serious he'd get his DNA sequence placed on a space probe. Failing that there's something he can do with his DNA information: Put it in the Yucca Mountain facility designed for storing nuclear waste. The place was chosen to be geographically very stable and to last a long time. The radiation signs outside will alert aliens that the facility is something special. They'll dispatch robots to investigate. The robots can recreate his DNA in an artificially constructed embryo using microfluidic devices, put the embryo in an artificial womb, and then Colbert Jr. can be born in the arms of a loving alien robo-mom.

By Randall Parker    2008 September 09 09:33 AM   Entry Permalink | Comments (5)
2008 August 19 Tuesday
Interstellar Travel Seen Unlikely

Getting to another lifetime seems unlikely even using the most advanced technologies.

The major problem is that propulsion -- shooting mass backwards to go forwards -- requires large amounts of both time and fuel. For instance, using the best rocket engines Earth currently has to offer, it would take 50,000 years to travel the 4.3 light years to Alpha Centauri, our solar system's nearest neighbor. Even the most theoretically efficient type of propulsion, an imaginary engine powered by antimatter, would still require decades to reach Alpha Centauri, according to Robert Frisbee, group leader in the Advanced Propulsion Technology Group within NASA's Jet Propulsion Laboratory.

Why go in the first place? Unless we could know in advance that travel to another solar system would provide us with a planet suitable for colonization what is the point in going? We have other types of planets to visit in this solar system. So we go to another solar system and it too has gas giants. For this I'm going to sit in a spacecraft for 50 years? I don't think so.

The development of rejuvenation therapies will eventually make it possible to travel to another solar system and live to see your spacecraft reach its destination. Though success will require design of spacecraft that are highly reliable for decades. Do not step on board until mean time between fatal failures is measured in the hundreds or thoiusands of years.

There's always the possibility that a discovery in physics will let us travel across the galaxy via another dimension. Hard to guess the odds of this happening.

You might be saying "but what about the opportunity to meet space aliens?". But there's a problem: either your microbes will kill them or their microbes will kill you. The odds of living on the same planet as creatures from another world seem pretty remote. Besides, they might be extremely xenophobic killers who enjoy hunting down and killing other intelligent species.

By Randall Parker    2008 August 19 10:45 PM   Entry Permalink | Comments (25)
2007 September 13 Thursday
Dubious Google Moon Rover X Prize

Google has announced a new prize for putting a rover robot on the Moon and the prize seems suspect to FuturePundit.

Nearly 40 years after the USA beat the Soviets to the moon Internet giant Google said Thursday it will give $20 million to the first private group to land a roving robot on the lunar surface — a prize likely to start a 21st-century space race.


For a team to win the $20 million grand prize, its vehicle must ramble at least a quarter-mile over the lunar surface and send video back to Earth. A $10 million second prize is reserved for the first spacecraft that can't rove but still transmits data from moon to Earth.

Another $10 million will go to super-rovers able to perform tasks such as roaming long distances or snapping pictures of equipment discarded by astronauts.

A prize goal should be achievable and preferably by a fairly small team. Prizes aimed at motivating large teams run up against limits to how many volunteers can work together and how they can agree on just distributions of prize money among other limits. Or the prizes just end up motivating a small number of large corporations. But a $20 million prize for the size of the task isn't profitable for a large corp even if they can be assured of success (which they can't for something this difficult).

David Noland of Popular Mechanics presents 5 reasons why no team will win this prize. Among the reasons? You have to succeed by 2012. Plus, the very obvious: $20 million is peanuts compared to the cost of designing all the hardware to get to the Moon and land and cruise around. The launch cost into orbit alone is going to be a lot more than $20 million.

Google is supposed to have a very smart staff. If those smarts really were applied to designing this X Prize and they really though this through then I'm left suspecting their motive. The prize is unworkable. It is a dumb way to try to achieve the stated goal. So are they just conning us? $20 million strikes me as a small amount of money for a large quantity of otherwise free publicity.

Prizes are better designed for more achievable smaller steps that take less time and resources so that individuals and small teams with the needed set of skills can get together and work toward some goal.

By Randall Parker    2007 September 13 08:14 PM   Entry Permalink | Comments (10)
2007 July 25 Wednesday
Psychological Problems On Polar Teams Problematic For Space Exploration

A substantial portion of the people who spend long periods of time at the poles suffer serious psychological problems.

While some people on polar expeditions savor a gratifying sense of achievement, the researchers said, 40 to 60 percent of them may suffer negative effects like depression, sleep disruption, anger, irritability and conflict with co-workers.

About 5 percent of these people endure psychological disturbances severe enough to merit treatment with medication or therapy, the researchers said.

"Polar madness can take a variety of shapes," Lawrence Palinkas, a University of Southern California anthropologist who wrote the paper in the Lancet medical journal along with Peter Suedfeld of the University of British Columbia in Canada, said in a telephone interview.

I'm thinking that genetic screening could serve a useful purpose in selecting crews for moon and Mars bases. Suggestion for NASA and the US National Science Foundation: Collect DNA samples from everyone who goes to spend years down in Antarctica and record how each person does. Then look for genetic variations that predispose people to do well or poorly in isolated and extreme conditions.

The US Navy could conduct a similar research effort on the genetics and psychological adjustment of submarine crews. Also, functional magnetic resonance imaging and other measures of cognition could provide patterns to look for that distinguish those who will do well or poorly in isolated conditions.

By Randall Parker    2007 July 25 10:00 PM   Entry Permalink | Comments (3)
2007 July 01 Sunday
Nuclear Rocket Proposed For Moon Return

Steven Howe, director of Idaho National Laboratory's Center for Space Nuclear Research, says a nuclear upper stage rocket could carry cargo from Earth's orbit to the moon more cheaply than a chemical rocket.

Howe envisions using a nuclear engine similar to one designed and tested in the 1960s called Nuclear Engine for Rocket Vehicle Application (NERVA). In the NASA-funded NERVA design, hydrogen gas is heated by nuclear reactions in a uranium reactor and expelled to produce thrust.

The higher efficiency of such an engine means almost 29 tonnes of cargo could be delivered to the Moon in a single Ares V launch, compared to 21 tonnes with the non-nuclear version. This would allow a 250-tonne lunar base to be constructed with only nine rather than 12 Ares V launches, Howe says..

Howe estimates that even with the added costs of developing the nuclear rocket that the total cost savings would be $1.5 to $2 billion. Of course, once the rocket gets designed and built and pays back its cost on the initial moon trips the cost savings would be even greater for additional trips to the moon or elsewhere.

Chemical rockets are a dead end. The chemicals weigh too much for the amount of energy they contain. To lower space travel costs we need to move beyond chemical rockets. Nuclear designs could work outside of Earth's atmosphere. If the US government wants to seriously pursue space exploration then nuclear designs warrant serious consideration.

By Randall Parker    2007 July 01 03:24 PM   Entry Permalink | Comments (8)
2005 November 20 Sunday
Objections To Multi-Generational Space Exploration

One way proposed for exploration to other solar systems is to have a space ship built that is so large, long lasting, and technologically advanced that it could travel for hundreds of years. The proponents of this approach argue for families to travel via such space ships so that they can give birth to children who will replace them as crew when the original generation gets old and dies. The idea is that the original generation would not live to step foot on some distant planet but their descendants many generations removed would some day colonize a planet orbiting a star many light years from Earth.

The most obvious objection to such a proposal is that why would anyone want to get on a spaceship and tavel to some place they will never see? Such explorers would be very unlike the human explorers of the last few hundred years who at least got to see amazing scenery even if, say, they didn't make it to the root of the Nile or the South Pole. But "explorers" embarking on a multi-generational trip between planets would have no such experiences. They'd step foot onto a rotating spaceship probably built in Earth's orbit and as the Earth receded from view they would have no new places to look at and investigate. They'd have a detailed understanding of their spaceship before even setting foot on it. They'd have stars to look at that would be little different than what they'd see from Earth's orbit.

But my biggest objection to a multi-generational spaceship colony is ethical: How dare some bunch of idealistic nut space explorers set out on a voyage that will condemn all their descendants for many generations to be born, live, and die in a relatively small confined area deep in space! The people who would be born, live, and die in such a vessel would be cut off from any planet, from scientific advances, technological advances, new cultural products, and from significant relationships with the bulk of humanity.

The act of the original generation of explorers would be incredibly selfish. Consider that the original generation of explorers would have direct experience of Earth societies and of travelling around and living in a variety of places on Earth. But the original generation would condemn many subsequent generations to a far narrower range of experiences and would deny the subsequent generations of the choice of whether to live in space or on Earth.

The subsequent generations born on the ship wouldn't be explorers in any meaningful sense. They'd be born on and live their lives out on a spaceship where there'd be nothing to explore. Their sole purpose would be to raise children so that those children would raise children so that some generation would some day see another planet.

Possibly the spaceship would be able to receive a laser beam transmission of information from Earth for at least part of the voyage. But this hardly makes up for the many losses that people would experience as a result of being born on a spaceship deep in space.

Worse yet, the whole sacrifice might turn out to be totally worthless in the end. The spaceship could suffer a catastrophic failure with the loss of all hands. Or an advance in propulsion made a few decades after the ship left orbit might allow much more rapid movement between planets.

But there is a very likely future change in circumstance where many decades or centuries long trips between the stars will become easier to justify both ethically and in terms of the satisfaction of the original explorers: The development of technologies which implement Aubrey de Grey's Strategies for Engineered Negligible Senescence (SENS) will allow the original explorers to live in a state of youthfulness for the entire length of a trip to another solar system. Long space trips would therefore no longer involve one generation deciding a very dismal fate of many future generations.

If you want to become a space explorer then your best chance of fulfilling that desire is to politically support the development of SENS technologies. Advocate for increased spending to accelerate the development of rejuvenating biotechnologies such as stem cells, growth of replacement organs, gene therapy, and techniques for getting rid of accumulated intracellular and extracellular junk. Rejuvenation with SENS would allow you to live long enough to be alive and young when interstellar travel technologies get developed and become cheap enough to be accessible to many people. Plus, the SENS technologies would make it possible for you to live long enough to survive the trip and actually set foot on another world. Alternatively, you could stay on Earth longer and wait for the development of faster than light technologies assuming FTL travel will ever be possible.

If you want to travel between the stars you might also want to advocate the development of technologies for hibernation and cryogenic freezing and restoration. A couple hundred years in a space ship would get awfully boring. However, once SENS is developed we'll have plenty of time to develop hibernation technologies.

By Randall Parker    2005 November 20 10:52 AM   Entry Permalink | Comments (54)
2005 October 21 Friday
Space Exploration Proposal: Edible Moon Buggy

To save weight on a future moon mission some students are exploring ways to construct an edible moon buggy.

The students task is to make an edible moon buggy. Eating your transportation is probably not always a good idea, admits project leader Walter Smith, at Ball State University in Muncie, Indiana, US. Neither is devouring anything coated in moon dust for that matter, but for college and middle school students aged 11 or 12, designing edible model rovers serves as a good learning tool, he says.

On the early part of a moon mission astronauts could do travelling with edible lunar rover. But toward the end of the mission they would shift toward working around their base and start eating parts of their rover.

A better way to save weight on food seems obvious though: grow the food while on the moon. Sunlight is not a problem. Though filters against the UV bands might be needed. Genetically engineer algae or other plant species to grow well under lunar conditions under filtered glass. Water would be needed of course. But genetically engineered organisms could process the human wastes of astronauts to get the water and grow food.

If soil which contains substantial amounts of oxyen could be found then only hydrogen would need to be transported to the moon. Research into hydrogen storage for earthbound energy applications may eventually produce better methods of hydrogen transport.

Oxygen from rocks for plants and for human breathing probably won't be a problem. The Hubble Space Telescope recently discovered areas of the moon with rocks rich in oxygen.

The Hubble Space Telescope has detected oxygen in moon minerals that future explorers could use for breathing, to make electricity, and for rocket fuel. Scientists say the findings will help them determine whether the amounts available in the lunar soil will be enough for future astronauts to use.

The orbiting Hubble observatory is usually aimed at extremely distant areas of the universe. But for a few days in August, the U.S. space agency, NASA, pointed it at the moon to look at the landing sites of the Apollo 15 and 17 missions of the early 1970s and a 45-kilometer wide impact crater on a plateau never visited by astronauts.

The Apollo missions had returned rock samples containing an oxygen-bearing mineral called ilmenite. Planetary scientist Mark Robinson of Northwestern University near Chicago says planners of future moon missions want to know if the plateau region contains an equally rich amount of ilmenite.

"All the minerals you find on the moon have oxygen in them, but ilmenite is special in the sense that it is relatively easy to break it apart to get to the oxygen," said Mr. Robinson.

By Randall Parker    2005 October 21 01:06 PM   Entry Permalink | Comments (1)
2005 April 07 Thursday
Superconductors For Magnetic Field To Shield Astronauts From Radiation?

Jay C. Buckey, associate professor of medicine at Dartmouth Medical School and a former Shuttle payload specialist, argues that advances in high temperature superconductors may allow creation of a protective magnetic field around a Mars mission spacecraft.

Just as a magnetic field protects Earth, it might be possible to put a magnetic field around a spacecraft. A coil of a superconducting material could produce a substantial magnetic field, which could, in turn, deflect the energetic galactic cosmic radiation. For a small-coil radius, the magnetic field would have to be quite strong (several Tesla) to be effective. A field of this size presents major structural and safety issues. The larger the coil, however, the weaker the magnetic field needs to be. A wire wrapped on a spool could be unwound in space into a large coil. As the radius of the coil approaches a kilometer or so, the field strength and current that is needed will drop to reasonable levels. This approach to shielding, called active shielding, potentially could keep radiation levels within the spacecraft at any desired level.

One of the big unsolved problems for a Mars mission is how to protect the astronauts from cosmic radiation while they are travelling between Earth and Mars and while on the surface of Mars. A physical shield around crew living quarters would require too much mass. Maybe an artificial magnetic field could solve the problem.

Buckey notes that the bone loss from zero gravity might be solved in time for a Mars mission by on-going biomedical research aimed at developing treatments for osteoporosis and other bone diseases. This fits a larger pattern: Most of the problems that make a Mars trip highly problematic will eventually be solved because of research and development advances that will come from industrial and academic labs motivated by profit and by the desire to solve problems we face down here on Earth.

A push for a Mars mission is unlikely to lead to funding of large numbers of areas of research well enough to appreciably accelerate the various fields of science and engineering that will produce those solutions. Why? The number of people wanting those advances for space exploration is far smaller than the numbers who want those advances for purposes on Earth. We will get better superconductors because the electric power industry and other industries on Earth see those superconductors as a way to lower costs by huge amounts. We will get better ways to control bone cells because of the desire for better ways to treat osteoporosis and bone injuries. We will eventually get better nuclear reactors and even fusion reactors which would be of considerable value for a Mars colony. But those reactors will come as a result of the widely recognized need for better replacements of costly fossil fuels down here on Earth.

Another big area of research is robotics. In two or three decades robotics should reach a point where robots could be sent ahead of a human mission to operate mining operations and construct habitats for humans on Mars. Will NASA and other space agencies get budgets large enough to appreciably accelerate the rate of advance of robotics? I'm guessing the answer is No.

I'm not arguing against funding specifically aimed at developing technologies in order to use them in space. In fact, if a larger fraction of NASA's budget was allocated to new technology development and less of NASA's budget was allocated to operating existing technologies ("existing technologies" examples include the expensive Space Shuttle and International Space Station) we'd be better off because technological advance would be accelerated. But a big push to put people on Mars in 20 years would mostly go to engineering development and manufacturing aimed at using existing proven lower risk technologies. Look at the International Space Station for an example of what big budget space hardware projects produce: Little new technology and lots of work for aerospace contractors.

My lack of enthusiasm for space exploration is in large part due to my perception that there are far better ways to spend money to accelerate the rate of scientific and technological advance than to do a new Moon mission or a Mars mission. Want advances in robotics? Fund robotics research. Want advances in energy? Fund energy research. Want advances in medicine that are useful for space trips? Fund osteoporosis research, stem cell research, tissue engineering, gene therapy, genome mapping, microfluidics, and many other areas of biomedical research.

Humans will go into space in larger numbers and travel greater distances once technologies developed for Earth-bound purposes mature to the point where future technologies provide solutions which lower the cost and increase the safety of space exploration by orders of magnitude. Changes in government policies that accelerate the general rate of advance of science and technology on Earth will do far more in the long run to bring about a new age of space exploration than would a push to start development of spacecraft and other equipment needed for a Mars mission.

By Randall Parker    2005 April 07 05:55 PM   Entry Permalink | Comments (14)
2005 April 06 Wednesday
Will Environmentalists Some Day Oppose Global Warming Of Mars?

Some day decades from now environmental extremists groups might try to sabotage a rocket launch carrying equipment to Mars for a massive climate engineering project. Artificially created octafluoropropane could trigger a melting of the Mars polar ice caps and make Mars much more capable of supporting life.

WASHINGTON—Injecting synthetic "super" greenhouse gases into the Martian atmosphere could raise the planet's temperature enough to melt its polar ice caps and create conditions suitable for sustaining biological life. In fact, a team of researchers suggests that introducing global warming on the Red Planet may be the best approach for warming the planet's frozen landscape and turning it into a habitable world in the future.

Margarita Marinova, then at the NASA Ames Research Center, and colleagues propose that the same types of atmospheric interactions that have led to recent surface temperature warming trends on Earth could be harnessed on Mars to create another biologically hospitable environment in the solar system. In the February issue of Journal of Geophysical Research-Planets, published by the American Geophysical Union, the researchers report on the thermal energy absorption and the potential surface temperature effects from introducing man-made greenhouse gases strong enough to melt the carbon dioxide and ice on Mars.

"Bringing life to Mars and studying its growth would contribute to our understanding of evolution, and the ability of life to adapt and proliferate on other worlds," Marinova said. "Since warming Mars effectively reverts it to its past, more habitable state, this would give any possibly dormant life on Mars the chance to be revived and develop further."

The authors note that artificially created gases—which would be nearly 10,000 times more effective than carbon dioxide—could be manufactured to have minimal detrimental effects on living organisms and the ozone layer while retaining an exceptionally long lifespan in the environment. They then created a computer model of the Martian atmosphere and analyzed four such gases, individually and in combination, that are considered the best candidates for the job.

Carbon and flourine would need to be concentrated from the Mars surface materials.

Their study focused on fluorine-based gases, composed of elements readily available on the Martian surface, that are known to be effective at absorbing thermal infrared energy. They found that a compound known as octafluoropropane, whose chemical formula is C3F8, produced the greatest warming, while its combination with several similar gases enhanced the warming even further.

My guess is that this would still be very difficult to do because a nuclear reactor would probably be needed to provide the energy for a chemical plant to fix the flourine to carbon. Also, a permanent human Mars colony or robots would be needed to carry out the needed work. The construction of a human colony would require much more material to be shipped to create livable conditions for humans far enough under the surface to provide protection from radiation.

The researchers anticipate that adding approximately 300 parts per million of the gas mixture in the current Martian atmosphere, which is the equivalent of nearly two parts per million in an Earth-like atmosphere, would spark a runaway greenhouse effect, creating an instability in the polar ice sheets that would slowly evaporate the frozen carbon dioxide on the planet's surface. They add that the release of increasing amounts of carbon dioxide would lead to further melting and global temperature increases that could then enhance atmospheric pressure and eventually restore a thicker atmosphere to the planet.

Such a process could take centuries or even millennia to complete but, because the raw materials for the fluorine gases already exist on Mars, it is possible that astronauts could create them on a manned mission to the planet. It would otherwise be impossible to deliver gigaton-sized quantities of the gas to Mars. The authors conclude that introducing powerful greenhouse gases is the most feasible technique for raising the temperature and increasing the atmospheric pressure on Mars, particularly when compared to other alternatives like sprinkling sunlight-absorbing dust on the poles or placing large mirrors in the planet's orbit.

How many gigatons would be needed? How much energy would it take to manufacture those gasses? How much energy would be required simply to gather and refine the raw materials?

Advances in robotics will eventually make climate engineering of Mars much easier to carry out. Fusion reactors (still a distant prospect) would probably weigh less than fission reactors and therefore would be easier to transport to Mars. This whole job will become much easier to carry out as a variety of new technologes are developed in the future for Earth-bound purposes.

I do not see Mars colonization as a cost-effective way to ensure the survival of the human race in the short to medium term. Mars is too costly to reach and too hostile to human life forms and to the life forms that humans use for food, medicine, and other purposes. At best only a handful of people could be transported to Mars to form a colony there.

If the goal is to ensure the human race's survival then the money spent on creating a Mars colony would be better spent on a number of other purposes. A great asteroid defense system could be built for a small fraction of the cost of setting up a Mars colony. Such a system would eliminate the biggest natural threat to continuation of the human species.

A massive volcanic eruption is another potential danger that could lead to billions of human deaths. Well, most humans wouldn't die from the initial eruption blast. The problem is that the sun would be blotted out (thereby rendering solar photovoltaic power useless). What we need is an uninterruptible power source. Today the only such power source we have is fission energy but cost and safety concerns have limited its use. Therefore if ensuring the continuation of the human race is the goal money allocated to accelerate fission and fusion energy research would be better spent than money allocated to a Mars mission.

Then we come to the human-generated threats to our continued existence. Most and perhaps all of those threats would probably pose a threat to a Mars colony as well.

First off, some humans may either intentionally or accidentally develop aggressive artificially intelligent robots. Well, Mars is not a place to go to escape from them. If robots some day become smart enough take over the Earth they will be able to build rockets and travel to Mars where they will be able to easily overrun any human Mars colony.

The nanotech goo idea is a human doom scenario where nanotech replicators start dividing uncontrollably and overrun the earth. The nanotech goo probably eventually lead to the overrun of a human Mars colony as well. The nanotech replicators would probably develop artificial intelligence because some of them would be programmed to construct complex systems. If the nanotech replicators become self-aware and highly organized they too would eventually mount a mission to Mars and wipe out humans on Mars.

About the only scenario where I see that a Mars colony might prevent the extinction of the entire human race is the case where a bioengineered plague would be unleashed in the human population. But my guess is we'd be better off spending money on biodefenses than on a Mars colony. Certainly that is true for the vast bulk of humanity that would still be here on Earth after a Mars colony is established.

There is a more fundamental reason why I oppose human species continuation as a justification for the creation of a Mars colony: I don't want to die either here on Earth or on Mars. Nor do I want to have the vast bulk of the people I know die while I (improbably) survive a while longer in a puny Mars colony. We ought to set our sights higher and aim at ensuring the continued life of the vast bulk of the human race, not just some small remote outpost living a tenuous existence in an extremely hostile environment. Efforts to set up a Mars colony seem to me misdirected as long as we do not have an asteroid defense system, fusion enengy, and last but not least, technologies for rejuvenation.

By Randall Parker    2005 April 06 11:27 AM   Entry Permalink | Comments (36)
2004 November 21 Sunday
Superconductor Magnetic Fields Might Protect Space Travellers

Artificial magnetic fields may some day protect humans travelling to the Moon or even further away.

Astronauts could one day be protected from harmful cosmic rays during a long haul spaceflight by a powerful magnetic bubble generated by their own craft.

A new project to investigate the possibility of fitting spacecraft with a “magnetosphere” of their own, underway at the Massachusetts Institute of Technology, US, recently received a cash boost from the NASA-funded Institute for Advanced Concepts.

This is a greater problem on the Moon and Mars and on a trip to Mars. In Earth's orbit the planet's magnetic field (a.k.a. magnetosphere which creates the Van Allen radiation belts of mostly proton particles captured around the Earth) provides some protection from cosmic and solar radiation. The atmosphere provides an even greater level of protection.

Humans can not live on the surface of the moon or Mars in structures that are only thick enough to contain atmosphere. A solar flare or burst in cosmic radiation would eventually kill humans unless a greater level of protection can be provided.

Radiation doses beyond the Earth's magnetic field are orders of magnitude higher than in Low Earth Orbit (LEO).

The amount of any radiation increase depends strongly on where one is located. If you are in a spacecraft outside the Earth's magnetic field, the radiation doses can be quite large (as much as tens of Gray—1 Gy = 100 rad), depending on how much spacecraft shielding there is around you. If you are in a spacecraft, such as the Space Shuttle or International Space Station, in Low-Earth Orbit, the doses are lower (up to tens of milligray)—specific values depending upon the altitude and inclination of the orbit and the amount of shielding provided by the spacecraft.

The creation of an artificial magnetic magnetic field powered by a mini-nuclear reactor or even by solar panels might allow humans to spend much longer periods of time on the surface of Earth's moon or Mars. Here is another reason to develop space nuclear reactors. More power is almost always useful.

By Randall Parker    2004 November 21 08:59 PM   Entry Permalink | Comments (1)
2004 September 21 Tuesday
Thermoacoustic Electric Generator For Better Space Probes

A more efficient form of conversion of nuclear heat to electricity may enable the building of more powerful space probes.

LOS ALAMOS, N.M., Sept. 16, 2004 -- A University of California scientist working at Los Alamos National Laboratory and researchers from Northrop Grumman Space Technology have developed a novel method for generating electrical power for deep-space travel using sound waves. The traveling-wave thermoacoustic electric generator has the potential to power space probes to the furthest reaches of the Universe.

In research reported in a recent issue of the journal Applied Physics Letters, Laboratory scientist Scott Backhaus and his Northrop Grumman colleagues, Emanuel Tward and Mike Petach, describe the design of a thermoacoustic system for the generation of electricity aboard spacecraft. The traveling-wave engine/linear alternator system is similar to the current thermoelectric generators in that it uses heat from the decay of a radioactive fuel to generate electricity, but is more than twice as efficient.

The new design is an improvement over current thermoelectric devices used for the generation of electricity aboard spacecraft. Such devices convert only 7 percent of the heat source energy into electricity. The traveling-wave engine converts 18 percent of the heat source energy into electricity. Since the only moving component in the device besides the helium gas itself is an ambient temperature piston, the device possesses the kind of high-reliability required of deep space probes.

The traveling-wave engine is a modern-day adaptation of the 19th century thermodynamic invention of Robert Stirling -- the Stirling engine -- which is similar to a steam engine, but uses heated air instead of steam to drive a piston. The traveling-wave engine works by sending helium gas through a stack of 322 stainless-steel wire-mesh discs called a regenerator. The regenerator is connected to a heat source and a heat sink that causes the helium to expand and contract. This expansion and contraction creates powerful sound waves -- in much the same way that lightning in the atmosphere causes the thermal expansion that produces thunder. These oscillating sound waves in the traveling-wave engine drive the piston of a linear alternator that generates electricity.

Note that they are not making any claims for this device as a propulsion system. Nuclear propulsion holds a lot of promise for space both manned and unmanned exploration. But even a more compact power source would allow space probes to either carry more sensors or beam back information at a higher speed or have fancier on-board computers for more complex decision-making.

By Randall Parker    2004 September 21 05:36 PM   Entry Permalink | Comments (0)
2004 September 15 Wednesday
Antarctic Telescope Could Best Hubble For Accuracy

A smaller test telescope already almost equalled Hubble in accuracy.

The images obtained from the astronomy test station at Dome C, 75° south and 3260 metres above sea level, were up to three times sharper and six times brighter than those from the best mid-latitude observatories, including those in Hawaii and Chile. On some nights, the images were almost as good as those from the Hubble Space Telescope.

Some astronomers would like to build a very large telescope at this site. Others would like to build a pair of infrared telescopes at the site and use them to search for planets.

Space is a very expensive place to do anything. Even a land-based telescope in Antarctica could be reached for a small fraction of the cost of a maintenance trip to Hubble. Buidling telescopes at this Antarctic site sounds like a great idea.

By Randall Parker    2004 September 15 01:41 PM   Entry Permalink | Comments (0)
2004 August 05 Thursday
Earth-Like Planets May Be Rare Around Other Stars

So far most stars with planets oribiting around them have gas giants with highly elliptical orbits that prevent Earth-like planets from developing in less elliptical orbits.

Researchers from the UK believe that our Solar System could have formed differently from many other star systems, making places like our home much more rare in the Universe. After examining the 100 or so known extrasolar planetary systems, they found that they probably formed in a manner different from our own Solar System - in a way that's hostile to the formation of life. Planets could form in several different ways, and how the Earth formed is actually quite rare. It will still be 5 more years or so before astronomers have equipment with the resolution to confirm this.

Martin Beer thinks our solar system's planets may have formed in a way that is rare as compared to how planets form around most stars.

Martin Beer of the University of Leicester, UK, and co-workers argue that our Solar System may be highly unusual, compared with the planetary systems of other stars. In a preprint published on Arxiv1, they point out that the alien planets we have seen so far could have been formed by a completely different process from the one that formed ours. If that is so, says Beer, "there won't necessarily be lots of other Earths up there".

But current ways of detecting extrasolar (not from our solar system) planets are biased toward planets that are the sort being found so far.

It will take a few years to resolve this debate. The vast majority of extrasolar planets have been detected by measuring the way a star wobbles as a result of the gravity of an orbiting planet. This technique is inherently sensitive to heavy planets with short orbital periods, so those are the ones we are finding.

NASA's planned Kepler mission, to be launched tentatively in 2007, will be able to find more Earth-like planets.

Kepler also is being designed to detect planets in an orbit like the Earth at the same distance from their star as the Earth is from our Sun. With a measure of the orbit of the planet and with information about the planet's star, scientists can determine if the planet might have liquid water on its surface and, perhaps, sustain life.

This is a familiar story in one sense: More advanced scientific and technological capabilities are accelerating the rate at which scientific discoveries can be made. Any speculation about the odds on the existence of intelligent species around other planets is fairly uninformed at this point. We will have far more data about the frequency of extrasolar planets with promising conditions within several years and our ability to listen for signs of intelligent life will grow by leaps and bounds in the coming years as well.

Also see my recent post Will Intelligent Alien Life Be Discovered Within 20 Years?

By Randall Parker    2004 August 05 01:49 PM   Entry Permalink | Comments (5)
2004 July 28 Wednesday
Will Intelligent Alien Life Be Discovered Within 20 Years?

Search for Extraterrestrial Intelligence Institute astronomer Seth Shostak argues that computers and radio telescopes will advance enough in the next two decades that within 20 years we will be able to scan all stars for radio transmissions that are the signs of intelligent life elsewhere.

If intelligent life exists elsewhere in our galaxy, advances in computer processing power and radio telescope technology will ensure we detect their transmissions within two decades. That is the bold prediction from a leading light at the Search for Extraterrestrial Intelligence Institute in Mountain View, California.

Seth Shostak, the SETI Institute's senior astronomer, based his prediction on accepted assumptions about the likelihood of alien civilisations existing, combined with projected increases in computing power.

Astronomer and Panspermia theorist Chandra Wickramasinghe thinks Shostak's prediction is reasonable.

"The criticism of this group has been to say that we've looked for intelligence for close on half a century and nothing has turned up, therefore there has to be nothing.

"I think that's an extremely false position to take.

"Forty years is too short a time to expect anything. We would be greedy if we expect the first hellos to come in the next 10 years.

"Twenty years is a more reasonable time to took forward to."

Even if an alien civilization is discovered that is 1000 light years away (i.e. it would take light 1000 years to travel between here and there) there may be people alive right now that will live long enough to carry on conversations with aliens. Once we achieve engineered negligible senescence people will be able to live youthful lives for thousands of years. So while conversations with aliens may require thousands of years to conduct such conversations could be carried out between individuals rather than between successive generations as representatives of civilizations.

I think the biggest problem with a conversation with aliens is that both we and the aliens would change so much between transmitting messages and receiving responses that we'd have little in the way of a meeting of the minds or a convergence of beliefs or mutual understanding.

Of course, if we could live for tens or hundreds of thousands of years then that opens up the possibility of travelling to meet aliens. But the trip would be so boring and even if the aliens sounded friendly we'd have no way of knowing how much they'd change before we travelled through space to the alien star system. By the time we reached their planet they might be gone or overrun by artificial nanotech creatures.

The other big problem with travelling to meet them is that either their microbes might be fatal to us or ours might be to them or to some aspect of their ecology. They might not want to risk having us as visitors.

By Randall Parker    2004 July 28 02:31 AM   Entry Permalink | Comments (18)
2004 May 12 Wednesday
Hubble Space Telescope Could Be Saved By Robot Mission

A robotic mission to replace the gyroscopes and batteries in the Hubble Space Telescope could probably be done if the money was made available to fund it.

The agency has budgeted about $300 million for a so-called controlled de-orbiting, but that might be only half the cost of a repair mission, particularly if it is attempted on a tight timeline. This could be bad news for Hubble supporters because, as Frank Sietzen reported recently for United Press International, there is only lukewarm support in Congress -- at a time of huge expenditures for the rebuilding of Iraq and record budget deficits -- for expanding the space agency's budget.

When President George W. Bush crafted his new space exploration vision for NASA last January, one of its key constituents was to retire the shuttle fleet and divert spending that originally was planned for the shuttle to develop a new generation of rockets. It could be difficult to justify diverting $500 million or $600 million of that effort for a Hubble rescue.

Put this in context. Why isn't there enough money available? The Bush Administration is cutting most areas of scientific research funding with the exception of national security and space programs. Yet the increase NASA's budget is to prepare for a return to the moon and eventually to make a big reality TV show produced on Mars (yes, I really do think a trip to Mars is a stunt with huge costs and minimal returns on investment).

Instead of trying to go to Mars the we could get a much bigger return on investment in space efforts by doing a lot of smaller things which each produce useful technologies. A robotic mission to Hubble is a great example of this approach. We'd get the extension of the life of a great scientific instrument along with useful technologies for doing space robotics. Another is the development of nuclear electric ion propulsion for a Jupiter probe. That program would be a useful stepping stone to the development of an asteroid defense system which itself would cost a small fraction of what a Mars trip would cost.

There are risks involved with the robotic approach.

Still, it will be risky. ''You can't underestimate the complexity and the dangers,'' said former astronaut Jeffrey Hoffman, a Massachusetts Institute of Technology aerospace engineer who made three spacewalks to repair Hubble in 1993. ``Suppose you open a door but can't put in the new instrument. Now you've got a light leak, and you've lost your telescope.''

Dr. David L. Akin, Director of the Space Systems Laboratory at the University of Maryland has been leading the Ranger space robotics program which has produced technology that may be used on the proposed robotic repair mission to Hubble. Akin points out that pursuing the robotic approach to fix Hubble will yield robotic technology that would be useful for other space applications such as working on other satellites.

"I would like to think somebody at NASA realizes that to do humans on the moon and Mars, you're going to need robotics to set up lunar bases, to build transfer vehicles. To relieve the crew of having to do the grunt work of toting and carrying and so forth, you need dexterous robotics," he says.

"Everybody's willing on kind of a high-level conceptual basis to say, ‘Yeah, that's absolutely true."

But while NASA has commissioned all sorts of computer graphics showing astronauts and robots working together, Akin notes, "they haven't been willing to put a penny into actually making it come true."

I think NASA should put more effort into many smaller projects for that involve the development of useful new technologies and less into extremely large grand programs.

By Randall Parker    2004 May 12 02:12 PM   Entry Permalink | Comments (1)
2004 January 09 Friday
Bush To Propose Moon Colony, Mars Trip, Ho Hum

President Bush wants humans to create a permanent Moon base in the late 2010s and to go to Mars in the 2020s.

President Bush will announce plans next week to send Americans to Mars and establish a permanent human presence on the moon, senior administration officials said Thursday night.

Bush won't propose sending Americans to Mars anytime soon; rather, he envisions preparing for the mission more than a decade from now, one official said.

If George W. Bush proposed a massive effort to develop enabling technologies and to work on basic scientific questions whose solution would provide the basis for enabling technologies for space exploration then I'd be thrilled. But of course that is not what he did. A trip to Mars is going to have all the long term impact of previous human trips to the Moon. The astronauts will go. They will plant the flag (or perhaps multiple flags from a multnational consortium). Then they will collect some rocks, do some tests, and eventually get back on their spacecraft and come home. Tens of billions will be spent and, while the Mars program will produce some advances, most of the effort will not go toward making big advances.

James Oberg says the Moon base will be useful for testing out technologies needed for a Mars trip.

A human presence on the Moon, says space expert James Oberg, would allow engineers to iron out the technical and medical challenges of a manned Mars mission, which require at least a year of space travel.

Oberg is right that a Moon base would serve as a useful test bed for trying out technologies necessary for a Mars trip. But a Moon base and a Mars trip both are very inefficient ways to advance space technology. One reason for this is that there is an inherent conservatism to any effort to send humans into space. Manned initiative always run on a schedule and technologies that might take too long to develop get axed in the planning stage. Also, the costs of manned programs are so large that most of the money has to be spent on approaches that are least risky and least likely to fail either in development or in use.

What ought to be driving NASA efforts is the goal of space colonization. In order to achieve that larger goal We need to strive to achieve technological goals that are much more ambitious than the next manned mission or even the manned mission after that. Given a sufficiently ambitious set of technological goals the priorities on what to fund and the overall approach taken toward manned spaceflight would undergo a radical change.

Do I hear you asking what should be the technological goals of NASA? Oh great, excellent question, glad you asked. Okay, here are some FuturePundit technological goals for the NASA manned spaceflight program:

  • Develop technologies that could be used to lower the cost of launch into space by orders of magnitude. The two main contenders are hypersonic ramjets or scramjets and nanotube-based space elevators.
  • Develop technologies that can cut the fuel weight needed for interplanetary travel and to increase trip speed. One leading contender to accomplish this is nuclear fission propulsion using either nuclear thermal or nuclear electric methods. Nuclear fusion and anti-matter are even more advanced approaches. Still further out on the horizon is the idea of laser beam propulsion.
  • Advance biological science and develop biotechnologies to produce the means to better adapt human bodies to zero gravity and lower gravity. For instance, pursue the development of gene therapies to retrain osteoclasts and osteoblasts to keep bones strong in low gravity. The research would produce valuable medical treatments for those suffering from osteoarthritis, osteoporosis, and other bone diseases.
  • Develop biotechnologies to produce food, drugs, and structures that would help to create self-sustaining human settlements on the Moon, Mars, and asteroids. Genetic engineering could be used to create bacteria that can produce a large assortment of drugs. Genetic engineering could also be used to create plants and algae that can be used to process waste and grow food.

The ability of humans to get into space, move in space, and live in space and on other planets is so incredibly primitive at this point that we ought to be concentrating on developing radically better technologies rather than spending tens of billions of dollars on space programs that utilize fairly small improvements on existing technologies. We are not going to be able to move out into the solar system and colonize other planets, moons, and asteroids with self-sustaining colonies until we make very large technological leaps in enabling technologies. Multi-billion dollar short visits to distance places by a small astronaut elite viewable by the masses as Reality TV may satisfy a lot of voyeurs. But voyeurism has never held much appeal to me. I don't want to watch astronauts on TV as they first step onto Mars for a brief visit. I want to be able to go there myself and live and work there for a period of years before moving on to Ganymede or to a radically reengineered Venus.

Update: In a column entitled "Mission to Nowhere" Anne Applebaum argues that the public is being deceived about just how far away we are from being able to move many humans out into space great distances.

If the average person on Earth absorbs about 350 millirems of radiation every year, an astronaut traveling to Mars would absorb about 130,000 millirems of a particularly virulent form of radiation that would probably destroy every cell in his body. "Space is not 'Star Trek,' " said one NASA scientist, "but the public certainly doesn't understand that." No, the public does not understand that. And no, not all scientists, or all politicians, are trying terribly hard to explain it either. Too often, rational descriptions of the inhuman, even anti-human living conditions in space give way to public hints that more manned space travel is just around the corner, that a manned Mars mission is next, that there is some grand philosophical reason to keep sending human beings away from the only planet where human life is possible.

It isn't impossible to sustain human life on Mars. It is just impossible to do so with the current level of technology. Make a trip to Mars go faster and the total amount of radiation absorbed en route would be much less. But a faster trip would require making major strides to advance science and to develop many new technologies. Send robots ahead to burrow underground and build highly sheltered living quarters and then a Mars colony would not receive such massive doses of on-going radiation. Develop better shielding materials for the trip to Mars and for living on Mars and, again, the radiation exposure could be drastically reduced. But all this takes lots of advances in science and technology. If only the $100+ billion spent on the International Space Station had been spent to fund labs down here on Earth we'd be closer to the day when trips to Mars will become possible. But NASA is not pursuing a long term strategy. Most of the space program amounts to a big reality TV production company producing footage that makes it onto the nightly news occasionally that makes the public feel good that something is being done to get humanity into space. But most of the money spent is a waste.

By Randall Parker    2004 January 09 02:08 PM   Entry Permalink | Comments (21)
2003 December 12 Friday
Earthlike Planets May Be Common In The Universe

Either we are not alone or there are some prime planets waiting to be colonized.

Astrobiologists disagree about whether advanced life is common or rare in our universe. But new research suggests that one thing is pretty certain – if an Earthlike world with significant water is needed for advanced life to evolve, there could be many candidates.

In 44 computer simulations of planet formation near a sun, astronomers found that each simulation produced one to four Earthlike planets, including 11 so-called "habitable" planets about the same distance from their stars as Earth is from our sun.

"Our simulations show a tremendous variety of planets. You can have planets that are half the size of Earth and are very dry, like Mars, or you can have planets like Earth, or you can have planets three times bigger than Earth, with perhaps 10 times more water," said Sean Raymond, a University of Washington doctoral student in astronomy.

Raymond is the lead author of a paper detailing the simulation results that has been accepted for publication in Icarus, the journal of the American Astronomical Society's Division for Planetary Sciences. Co-authors are Thomas R. Quinn, a UW associate astronomy professor, and Jonathan Lunine, a professor of planetary science and physics at the University of Arizona.

The simulations show that the amount of water on terrestrial, or Earthlike, planets could be greatly influenced by outer gas giant planets like Jupiter.

"The more eccentric giant planet orbits result in drier terrestrial planets," Raymond said. "Conversely, more circular giant planet orbits mean wetter terrestrial planets."

In the case of our solar system, Jupiter's orbit is slightly elliptical, which could explain why Earth is 80 percent covered by oceans rather than being bone dry or completely covered in water miles deep.

The findings are significant because of the discovery in recent years of a large number of giant planets such as Jupiter and Saturn orbiting other suns. The presence, and orbits, of those planets can be inferred from their gravitational interaction with their parent stars and their affect on light from those stars as seen from Earth.

It currently is impossible to detect Earthlike planets around other stars. However, if results from the models are correct, there could be planets such as ours around a number of other suns relatively close to our solar system. A significant number of those planets are likely to be in the "habitable zone," the distance from a star at which the planet's temperature will maintain liquid water on the surface. Liquid water is thought to be a requirement for life, so planets in a star's habitable zone are ideal candidates for life. It is unclear, however, whether those planets could harbor more than simple microbial life.

Suppose there are a lot of planets which are similar to Earth in size and in the amount of radiation they receive from their own suns. Even if some of them do not contain sentient lifeforms they still may have native life forms and those life forms may be incompatible with human life. Imagine pathogens that human immune systems couldn't even recognize let alone effectively fight. Or all native plant matter might be poisonous not only to humans but to any plants humans would bring to grow on such a planet.

It is incredibly common in science fiction movies and television shows for humans to mate and reproduce with aliens and to find edible food on distant planets. But if there is life on other planets both of these possibiliities are very unlikely. Other lifeforms will probably use different combinations of compounds for genetic encoding and for building tissues. Species on other planets may use amino acids to build proteins but probably not the exact same set of amino acids humans use. Ditto for sugars and other biological compounds.

The real tragedy is that even if humans and sentient species from other planets could get along and even if other sentient species lived under similar levels of gravity and atmospheric pressure and also were oxygen breathing it would probably be necessary to never have direct physical contact due to fears that pathogens would jump from one species to another with deadly results.

By Randall Parker    2003 December 12 01:24 AM   Entry Permalink | Comments (14)
2003 September 30 Tuesday
Explore Parallel Universes With Gravity?

Writing for The Christian Science Monitor Michelle Thaller reports on the Brane Theory for an eleven dimensional universe.

There are some theoretical reasons to believe that there are other branes out there besides our own, separated from us by a dimension we can't travel in. Cosmologists are getting pretty excited about a new model of how the universe began, with one or more branes interacting with each other. There may even be observational evidence of this in the microwave background radiation, leftover heat from the very beginning of our universe. The implications of this theory are staggering. Not only is the door left wide open to the possibility of entire parallel universes existing out there in the Bulk, but now we have the real possibility that gravity may allow us to explore them, to a very limited degree.

Brane is short for membrane and is a reference to the idea that our 3-dimensional universe might be enclosed in a higher dimensional membrane of some sort.

By Randall Parker    2003 September 30 11:14 AM   Entry Permalink | Comments (4)
2003 February 16 Sunday
What Biotech Could Do For Space Travel

When most people think of space travel they typically think of rockets, spaceships, propulsion systems, spacesuits, and structures to ship to Moon or Mars colonies to live in. The key role that biotechnology could play in enabling space travel and colonization is too often ignored. I'd like to bring up a number of ways that biotechnological advances could enable space travel and colonization.

One big problem with space travel is that the costs per pound or kilogram sent are incredibly high. Spacefarers need ways to make consumables en route and once they have arrived at their destinations. A number of problems need to be solved to make space travel and space colonies feasible. Some of those problems must be solved with a biological approach. Others, while they could be solved with biotech, may be solvable using other approaches as well.

Human Hibernation

This is an approach for reducing consumables on a long space voyage and also for reducing the psychological strain of long journeys in small spaces.

One approach is to try to replicate the state that hibernating animal species enter into. The study of the molecular biology of hibernation may yield valuable information. It may not be possible to safely put a human body into a hibernation-like state for weeks and months at a time. Species that hibernate may have metabolic differences that are so drastic that adjusting humans to have the ability to hibernate for a long time might very difficult. One objective of hibernation research should be to discover how extensive the metabolic changes are in hibernation in order to determine whether hibernation is an approach worth pursuing.

A more limited adjustment that increases the number of hours slept per day could probably be achieveable with much less modification of human physiology.

Another approach would be to slow the metabolism down into a state that mimics the state achieved by those practicing calorie restriction. Drugs that reduce appetite and slow down metabolism would also decrease the rate of consumption of food. This approach would not provide as much relief from the strain of extended confinement.

Adjust Human Bodies to Low and Zero Gravity

Techniques for manipulating human metabolism to adapt it to space travel and to low gravity Mars and Moon colonies are probably not optional for colonization. Mars has only 0.377 of Earth's gravity and the Moon is even worse with only 0.166 of Earth's gravity. It is likely that extended living in such low gravity environments will cause problems for human health. Bones may weaken so much that return to Earth may become impossible or extremely difficult. Muscles similarly will atrophy. Plus, the lower need for blood circulation may cause inflammation and atherosclerosis. It is likely there are other longer term effects of low and zero gravity living that will need to be solved.

Centrifugal spaceships can only solve the problem that low gravity poses for human health for the trips to and from Moons and planets. But since moons and some planets have lower gravity than Earth the problem needs a more general solution. That solution must be a method of manipulating human metabolism to adapt it to low gravity living.

A Closed Biosphere

Make a closed cycle biosphere for space voyages in order to reduce the weight in consumables that must be sent with a human crew. Microorganisms could be genetically engineered to recycle waste and produce food. If a spaceship is nuclear powered then it will have enough energy to warm and provide light to microorganisms that could be genetically engineered to break down human waste to feed to still other genetically engineered cells that would create food.

The ability to run a closed biosphere implies the ability to grow food. This will be useful not just for reducing weight requirements for food eaten during long journeys to colonies but also for the food eaten at the destinations. Closed biosphere research is probably the most important area where work is needed to support colonization.

Structure producing plants and microorganisms

Mars colonists will need materials suitable for building structures. Chairs, bedframes, baby cribs, walls, and ceilings are just a few of the types of structures they will need to be able to build. Trees grow too slowly and take up too much space. What is needed is a way to use energy from a nuclear power plant to create organic materials to feed organisms that can create materials with wood-like qualities.

Textile Fiber Producing Microorganisms

Mars colonists will need clothes. They'll need bedsheets, pillow cases, napkins, towels, rags, and materials for furniture covering. Any need for textiles that exists on Earth likely will exist on Mars as well. Genetic engineering could produce plants capable of making fibers suitable for textile production. Either the genes for making silk could be genetically engineered into microorganisms or something similar could be done with cotton plant genes. It might even be possible to use cotton plant cells but engineer them to make cotton fibers without being attached to a full plant.

Medicine and Vaccine Producing Plants and Microorganisms.

This is a hard one to solve because there are so many drugs that would eventually be useful on Mars. Each drug requires its own series of synthesis steps.

Some vaccine producing plants are under development. But they are less useful on Mars in part because there won't be as many diseases to contend with. Colonists won't exactly have to worry about getting malaria from mosquitoes. Plus, their numbers will be so low initially that diseases that pass from person to person won't have a way to be maintained. Plus, all the colonists can be vaccinated before they leave Earth.

Another reason vaccine creation on Mars will probably not be reliant on plants or microorganisms is that a single device capable of making DNA vaccines could make all the types of DNA vaccines needed. While drugs each need their own unique set of chemical synthesis steps DNA vaccines all will use the same series of 4 (Adenosine, Cytosine, Thymidine, and Guanidine) chemical letters to make them. A single general purpose DNA sequencer that can be programmed to make any DNA sequence could be used to make all types of DNA vaccines. A lot of groups are working on DNA vaccines and it is reasonable expect that the optimal DNA sequences for a wide range of DNA vaccines will be available in 10 or 20 years.

Priorities for Research and Development

Most of the items above would have plenty of commercial uses here on planet Earth. Most of the advances needed will be done for other reasons.

The effects of low gravity effects on the human body have got to be the biggest set of problems. Progress will be made on these problems due to biomedical research efforts for problems that humans have here on Earth. Scientists will figure out how weight is used to signal bones to grow and the mechanisms by which muscles are signalled to grow will be elucidated as well. The knowledge gained from such reseach will be useful in treating aging-related changes and for injury healing. While that research will provide a firm foundation upon which to develop drugs, gene therapies, and other techniques to deal with extended living in low gravity environments a substantial amount of research work will still have to be done for that specific purpose. Humans are adapted to the force of one Earth gravity.

Beyond adapting humans to low gravity environments the biggest need is to be able to produce consumables for longer term living. The spaceships used to travel to Mars or the Moon will provide some shelter. Clothing made of long-lasting materials can last for years. So there shouldn't be much need to produce new clothing for the first few years. Methods to grow food and to maintain a closed biosphere would address another really big need.

We do not just need bigger and better rockets and spaceships in order to set up space colonies on the Moon or Mars. There are difficult problems in biology that must be solved. The biggest set of problems concern the human body. We are designed to live in a very narrow range of conditions. Even if we could cheaply go to other places we could not sustain human settlements under conditions for which we are not adapted. Until the basic problems are solved we can only visit other places and then only at great expense.

By Randall Parker    2003 February 16 11:03 PM   Entry Permalink | Comments (18)
2003 February 11 Tuesday
Space Shuttle Replacements And Space Exploration

On the NuclearSpace.com website Robert Zubrin argues that the Space Shuttle is a very inefficient way to put people into space.

In truth, the shuttle is not a space lift vehicle at all; rather, it is a self-launching space station. It is not a truck with a heavy hauling capability, it is a Winnebago whose primary function is to move itself. The shuttle at lift off has the same thrust as a Saturn V moon rocket, yet it has only 15 percent of the payload, because 85 percent of the mass it delivers to orbit is that of the orbiter itself. This is why it is the least efficient payload delivery system ever flown.

Zubrin argues that the Shuttle's rockets could be used more productively with an unmanned upper stage to put payloads into orbit that are as big as what the Saturn V could launch. While this might be a good idea given where we stand right now it demonstrates just how far we haven't progressed since the Apollo program was cancelled. If we make the right decision we can have as much launch capability as the Saturn V provided. Oh geez, why am I not excited?

Zubrin also argues for the creation of a new human carrying spaceplane which would not try to carry cargo with the humans and which therefore would be small enough to sit at the top of expendable rockets (Delta or Atlas) and which would be able to fly back to Earth. It would be able to fly itself away from a Delta or Atlas that failed and, since it would sit entirely above the rocket, would not be susceptible to damage from pieces falling off the rocket. This is not a new idea. As John Pike points out in a New York Times article the idea was under discussion in the 1960s.

Mr. Pike said the concept of a reusable plane on top of an expendable rocket dates from the 1960's, before NASA decided on the shuttle. "When you sit down and do the math, if all you're trying to do is get people back and forth from a space station, that's what you want," he said. "That's the appropriate degree of reusability. After four and a half decades of the space age, the technology to do that is readily at hand. There's essentially no research required. It's literally off the shelf."

At this point it seems likely that NASA will use existing technology to build this kind of design that they should have pursued 40 years ago. They will probably build something better than what they could have built back then because materials science has advanced in the meantime and computers can test and change designs more rapidly than humans could in the pre-CAD/CAE era. But they won't push the envelope of what is possible when they build that spaceplane.

It is probably true that with current technology we could mount a human mission to Mars. Some proponents of a Mars mission argue that since it is technically possible to do it now we should therefore do it because it would be a huge step forward in human exploration. But while it would be a huge step forward in terms of the uniqueness of the accomplishment would it be an enabling step toward later steps? I think we ought to stop, step back, and look at what happened as a result of the human Apollo mission to the Moon. Once the trip had been made people quickly lost enthusiasm because basically it was expensive to do and there wasn't any way (absent even greater on-going expense) to maintain a permanent human settlement on the Moon. The Apollo program did not produce technology that made human presence in space or on the Moon into an economically viable proposition.

As long as the human presence in space is so expensive that it requires widespread public support to get tax money to fund it we are not going to go into space in any sustained fashion. We might be able to get public support to a high enough level at some point to do a Mars mission. But is it wise to do so? After it is over and the astronauts have returned to have their tickertape parade we could find ourselves back in the same position we were in as the Apollo program wound down. If we do not make technological advances that make a human presence cost-effective to maintain then a human presence isn't going to be maintained, let alone grow.

If we are to move into space in large numbers and sustain a human presence in space then we should put the development of new enabling technologies ahead of the building of hardware to execute large missions using existing technology. Building hardware and running missions with existing technology does not move us any closer to the creation of permanent self-supporting human settlements on the Moon or Mars. What it does is it delays the development of those settlements because it burns thru money doing things that do not push the technological envelope very far. If we compare where we are technologically to where we need to be to make self-sustaining settlements it is clear that there is a very large gap. We should make the closing of that technological gap be our highest funding priority. Among the technologies we should pursue toward that end:

  • Nuclear propulsion for human spacecraft.
  • Scramjet launch vehicles. Advances would need to be made in both materials science and in our understanding of the physics of the intake air in hypersonic flight.
  • Nanotechnology for making a cable to reach up into orbit.
  • Biological advances to discover how to prevent muscle and bone loss in low and zero gravity environments.
  • Biotechnological advances to grow foods and medicines for a remote colony.
  • Biotechnological advances to grow structures and fibers for a remote colony.

If there is to be a government-funded space program then it should pursue the achievement of longer term goals. The pursuit of shorter term goals has plagued the space program from its inception. The result after over 40 years of human space flight is a very expensive, unreliable and dangerous set of technologies for supporting human activity in space. It is time to learn from our mistakes and commit to working on the hard technical problems that must be solved to enable permanent self-sustaining human settlements off of planet Earth.

Update: Paul Krugman calls for an end to manned spaceflight using current rocket technology.

Does that mean people should never again go into space? Of course not. Technology marches on: Someday we will have a cost-effective way to get people into orbit and back again. At that point it will be worth rethinking the uses of space. I'm not giving up on the dream of space colonization. But our current approach -- using hugely expensive rockets to launch a handful of people into space, where they have nothing much to do -- is a dead end.

At the risk of sounding repetitive: We should work on making the large leaps in technology that would enable space travel and colonization to be done on a larger scale and on a more sustainable economically self-supporting basis. Money spent operating current technology is money poured down the drain.

By Randall Parker    2003 February 11 04:22 PM   Entry Permalink | Comments (40)
2003 February 10 Monday
Richard Muller On Benefits Of Unmanned Space Efforts

UC Berkeley Physics Professor Richard Muller argues that the biggest NASA achievements in space in the last two decades did not involve manned missions.

Hubble aside, what would you name as the really glorious achievements of NASA in the last 20 years? My favorite: the discovery that every moon of every planet is significantly different from every other moon, a result completely unanticipated and still not understood. One might also pick the amazing success of weather satellites. Or the remarkable pictures you get from your satellite TV system. Those in the know might pick our space spy systems. Then there’s GPS—the Global Positioning System, used to guide airplanes, boats, hikers, automobiles as well as soldiers and smart weapons. These projects have one thing in common: they were all unmanned.

Note that some of the achievements Muller lists were not done by NASA. GPS was developed by the military. Weather satellites are similarly funded by a different government agency (NOAA? National Weather Service? one of those). For the amount of money that has been spent on manned space trips over the last 20 years we could funded an enormous amount of space science as well as a great deal of technological development of radically more advanced space launch and space travel technologies.

By Randall Parker    2003 February 10 01:42 PM   Entry Permalink | Comments (1)
2003 February 08 Saturday
Gregory Benford: Beyond the Shuttle

Science fiction writer and physics professor Gregory Benford has an excellent article up about NASA and the future of manned space flight.

Perhaps the only good thing about this disaster is that it will prompt NASA to rethink the design of manned spacecraft from first principles. Foremost is that the more complex a spacecraft is, the more things can go wrong.

The safest manned descent module was also the simplest: the Soviet "sharik" descent capsule, which was used by Vostok and Voskhod craft, and also in many unmanned missions since. It was just a sphere with the center of gravity on the side with the thickest ablative thermal shielding, so it was self-stabilizing. Even if the retrorockets failed to separate, it could re-enter safely. Simple ballistic craft that do not fly are also (relatively) simple.

With a spaceplane like the shuttle, however, you are not only committed to a complex shape, you are also committed to using brittle ceramic materials for thermal shielding. The first item on NASA's agenda will be to revisit the tiles issue.

There is the old KISS principle of engineering: Keep It Simple Stupid. NASA's Shuttle design violates that principle in a big way and the result is an expensive, unreliable, and unsafe spacecraft. Benford argues for inherently more reliable designs that do not rely on so many things to go right in order to work.

Benford argues for the development of a centrifuge in space because it is needed for human health during extended periods in zero gravity. That seems like the wrong solution to the problem. It makes much more sense to fund basic research into how muscle and bone growth is regulated. If control could be achieved over those processes then humans could be adapted to zero gravity living. This would be beneficial for more than just zero gravity conditions. As Benford points out, Mars has only 0.377 of Earth's gravity. But the problem of insufficient gravity for human health is even worse for a Moon base with the Moon having only 0.166 of Earth's gravity. Plus, a space hotel at the L1 Earth-Moon Lagrange point would be cheaper to build and operate if it didn't have to be a large centrifuge.

An even more compelling reason to solve the human gravity problem with a biological approach is that the research would surely produce valuable information for the treatment of osteoporosis as well as for healing bone and tissue injuries. For years one justification offered up for space exploration is that it will yield valuable technological spin-offs that will benefit us down here on Earth. A biological approach to solving the gravity problem would produce medically valuable research results.

Benford also argues for developing a closed biosphere. Certainly permanent Moon and Mars bases should have the ability to grow their own food. This problem also would best be solved in biological research. Tissue engineering techniques could be used to develop cell lines that can grow edible steak meat and chicken meat. Plant and animal cell lines could be developed to produce optimal quantities of vitamins and other nutrients. This is another avenue of research that could be pursued to enable space exploration that would generate technological spin-offs with commercially valuable Earth-bound applications.

Biotechnological approaches could address many other problems that would need to be solved in order to maintain human populations on permanent Moon and Mars bases. One problem is medical. One could take as much of each type of drug as might conceivably be needed. But there are too many drugs and it would be difficult to predict needs. One approach to solving this problem would be to genetically engineer strains of bacteria, yeast or other organisms to produce a large variety of drugs. One would need to take along frozen samples of each strain of bacteria that produced a given type of drug. Then when the need for a drug arose that bacteria could rapidly be cultured to grow and produce the needed quantity.

We should not rush to make a trip to Mars. We should instead identify all the technological problems that need to be solved in order to make a Mars trip and permanent establishment of a Mars base safe and affordable. We should not push out into space using barely adequate technology. We should put technology development first. Nuclear propulsion for much faster interplanetary travel, biological techniques to adapt to zero gravity, and biological technologies for growth of food and drugs, are just a few of the areas that a forward thinking space program would fund.

By Randall Parker    2003 February 08 02:30 PM   Entry Permalink | Comments (5)
2003 February 07 Friday
Space Travel Will Be Enabled By Non-Space Technologies

Rand Simberg argues that we need low cost reusable space launch vehicles.

We need to recognize that we have a chicken and egg problem. We will only get low costs and reliability with high activity levels, and we will only get high activity levels with vehicles designed to sustain them, at low cost (and that means not throwing them away).

In the comments section of that post Michael Mealling argues that only a business approach to space will make space development happen.

IMHO, there are two methods: 1) we all build businesses unrelated to space and create enough wealth among us that we can pay to have that value network built for us (there is imperical evidence that this works) 2) we figure out disruptive technologies/products/business methods that change the underlying assumptions about space and its relationship to people on the planet. The first one is tractable and relatively easy. The second is much more fun and potentially paradigm changing but extremely hard.

Let me argue a different viewpoint: The vast bulk of the technologies that will eventually enable significant human movement into space will come from outside the aerospace industry and will not come from people whose motive it is to develop technologies that will enable the development of cheap safe spaceflight. The US Department of Defense will have an FY2004 budget of around $379 billion dollars. In spite of this the DOD increasingly looks for ways to more rapidly incorporate civilian technologies into military weapons systems. NASA, with a budget of only $15 billion dollars (little of which goes to the development of new space launch technology) is even more in the position of user of the best new private sector technologies (and then only when it gets around to designing something new).

NASA has been locked for years into supporting the continued use of old technologies to produce sentimentally appealing human space missions in the short term. Whether the fault for this lies in NASA or Congress or Presidents or the American people is really besides the point. Because of the continued inability of NASA to focus on long term technological development the technological advances that will some day enable the economic development and colonization of space will not come from NASA funding.

It makes sense for NASA to abandon the Space Shuttle and ISS in order to focus on new technology development. But my own prediction is that the only way that is going to happen in the short term is if the loss of the Columbia is found to have been due to a design flaw in the Space Shuttle that can't easily be fixed. NASA and Congress are too committed to the Space Shuttle and ISS. The film clips the Shuttle missions create are seen as glorious in the minds of too much of the public. Political leaders are not at all eager to educate the public to see the Shuttle and ISS as big mistakes (after all, who made those mistakes?). Nor are they going to tell the public that the deaths of the astronauts who die on Shuttle flights do not contribute to the advance of our ability to move out into space (even though that is obviously the case). In the face of the widespread belief in myths about what our current human space flight program accomplishes it seems unlikely that NASA will be ordered to abandon the Shuttle. It seems even more unlikely that NASA will instead be assigned as its the top priority the development of new space-enabling technologies.

Given that NASA is unlikely to become more effective and that other national space programs are less well-funded and even less ambitious where does that leave the future of manned space travel? We need to make very large technological strides in order to get out of our current rut of high costs and low safety and reliability for human space launch. But until future Shuttle losses eventually end the Space Shuttle program by attrition NASA is not going to put much effort into radical technological advances. Even when NASA gets around to developing a new type of shuttle it will do so in such a hurry to meet an immediate need (yet another Shuttle loss being the most likely proximate cause) that the new design will just incorporate the best technologies available at that point. Therefore NASA will not try out many experimental design concepts as prototypes and will instead opt to pursue a fairly conservative design utilising existing knowledge.

Luckily there is a silver lining in this pessimistic story. The overall rate of scientific and technological advance is accelerating. While Moore's Law may slow down the rate of increase in processor speeds the rate of advance in computer microprocessors (eventually using quantum computing or biomolecular computing) will still produce computers that are orders of magnitude faster in the next few decades. Also, fiber optics and mass storage will continue their own rapid rates of advance. All of these technologies along with advances in mathematical algorithms for simulating designs and physical phenomena will combine to provide better computer aided design and engineering tools. Therefore future spacecraft development efforts will be able to produce much more optimized designs.

General physics, chemistry, and biology continue to advance. Advances in materials science and nanotechnology will provide many new materials and fabrication techniques for use in space launcher design. New types of structural and sensor materials will enable the implementation of spacecraft whose performance greatly exceed the best spacecraft that could be built today. Computer advances combined with sensor advances to make new kinds of control systems will enable the creation of designs that would otherwise not be possible.

The development of a significant human presence in space could in theory be accelerated by a focused attempt to develop enabling technologies specific to spaceflight. Before the advent of computers with sufficient throughput to simulate the performance of advanced supersonic ramjet designs and other advanced design approaches it would be possible to develop many prototype concepts and to try many prototype materials in prototype experimental spacecraft. Such an effort, while risky, might produce a much better design. But the political environment argues strongly against that the pursuit of such a high-risk high-payoff approach. Instead, advances in space launch technology will have to await the creation of a large range of enabling technologies which will originally be developed for other purposes.

Space enthusiasts who do not like this prognosis do have one option: promote arguments to the general public and to opinion leaders about the benefits of pursuing a more radical path for the development of space technologies. A reasonable component of such an argument would be to advocate the split of NASA to put its scientific space studies work (i.e. studying planets, asteroids, stars and all other stuff up there) into an agency dedicated to that purpose. Then another agency should be dedicated to the development of science and prototype technologies focused on lower cost launchers and human space travel.

By Randall Parker    2003 February 07 03:44 PM   Entry Permalink | Comments (8)
2003 February 05 Wednesday
Aircraft and Space Shuttle Accident Rates

We have now lost both the Challenger and the Columbia. That's 40% of the Shuttle fleet. It's time to seriously reexamine the US space program. Should the Shuttle continue to be operated? Should a new kind of shuttle be designed? What should be the criteria used to answer these questions? The debate about the future of the US Space Shuttle should be a debate about how we can make space travel much safer, more reliable, and lower in cost. These are interrelated goals. Unreliable launchers and passenger carrier spacecraft are more likely to be lost. Loss of a launcher is both fatal for the crew and incredibly costly. Higher reliability equipment is safer and less costly to maintain.

Let's compare aircraft safety to Space Shuttle safety.

The 1995 fatal accident rate per million miles flown for these large scheduled airlines declined to 0.0004 from 0.0008 the year before. Based on 100,000 departures, the fatal rate was 0.024, down from 0.050 in 1994.

Scheduled commuter or regional airline fatalities dropped to 9 persons from 25 in 1994 for the lowest level since 1990. The fatal accident rate fell both in terms of million miles flown to 0.003 from 0.005 in 1994, and from 0.083 to 0.057 in terms of 100,000 departures. It was the fourth consecutive annual decline in the fatal accident rates.

In 1995 the fatal accident rate per 100,000 departures for the airlines flying the smaller aircraft was 0.057 and impressively was less than half that for the big jets operated by the majors. Assuming they are talking about number of accidents and not how many people died in each accident (anyone know?) then to compare that to the Space Shuttle record we compare the 2 fatal Space Shuttle accidents out of 113 flights. That works out to 1770 fatal accidents per 100,000 flights. 1770 for the Shuttle divided by 0.057 for smaller commercial aircraft works out to an accident rate that is over 31,000 times greater for the shuttle than for small craft commercial aviation. When compared to large craft commercial aviation using 1995 again as a comparison point (note that there is fluctuation from year to year because there can be clusters of accidents in a year just by chance - but the trend in commercial aviation is toward ever lower accident rates) we see that the Shuttle is over 73,000 times more dangerous.

James Dunnigan has a table showing failure rates of launchers that have been used more than 100 times each. The US Space Shuttle has a lower failure rate than the other launchers. The failure rates range from 5% for the Russian R-7 Soyuz and European Ariane 1-4 to 14% for the US Atlas. In his article Dunnigan argues that the International Space Station (ISS) is the major justification for the US Space Shuttle. But before we get to that let's think about what these failure rates mean.

If the best space launch vehicle in existence has an failure rate of 2% and the rest are worse this argues that achieving an acceptable level of spacecraft passenger safety can not be done by developing small incremental improvements to current launch vehicle technology. One option is to design passenger carrying spacecraft to integrate with the launchers in a way that allows the spacecraft passengers can survive launch failures. Such a technology was built into Apollo (the Apollo Escape Tower for pulling the CM away from a failing rocket). Another, and not mutually exclusive approach, is to develop a launcher technology that is inherently more reliable than current technology. We can't expect to implement either of these approaches with the Space Shuttle. Technologies that would offer greater than order-of-magntitude improvements in safety and reliability can not be retrofitted into existing designs. Limitations inherent in the original design of the Space Shuttle makes it totally inappropriate as a target for attempts to make big strides in the reliability and safety of human space travel. We need to start over from scratch.

In 1950 there were 2,482 thousand aircraft departures, 19,102,905 passengers carried, and 6 fatal accidents. In 1997 there were 8,157 thousand departures, 598,895,000 passengers carried, and 3 fatal accidents. Fatal accidents per million aircraft miles flown dropped from 0.0126 to 0.0005. The number of fatal accidents per million miles flown was about 25 times greater in 1950 than in 1997. This is the standard against which spacecraft should be compared. The Space Shuttle is at least 3 orders of magnitude more dangerous than passenger aircraft from 1950. Could the aircraft in the fleet of 1950 have been continually modified to make them as safe as a passenger aircraft manufactured 20 or 30 years later? Of course not. Better design and fabrication techniques produced later designs that were inherently more reliable.

But let's go back even further to look at aircraft safety in 1938. That's when some US government agency was created that started tracking aircraft safety. It is not clear from the table what kind of fatal accident rate measure they were using. But compare the 1938 rate of 11.9 to the 1950 rate of 5.0 and the year 2000 rate of 1.1. The 1938 rate of fatal accidents was about an order of magnitude higher than it is now. But its still more than two orders of magnitude lower than the fatal accident rate of the Space Shuttle.

1938 was 35 years after the first aircraft flight of Orville and Wilbur Wright on December 17, 1903 at Kitty Hawk North Carolina. Manned space travel began on April 12, 1961 when a Soviet air force pilot, Major Yuri A. Gagarin, made an orbit of the Earth. So manned space travel is over 40 years old. Space travel into Earth's orbit is orders of magnitude more dangerous after 40 years than aircraft travel was when it was only 35 years old.

Aside: If anyone has aircraft safety data that goes back to the era of biplanes in WWI (leaving aside casualties from war) then please pass it along. It seems quite possible that aircraft safety was never as dangerous as spacecraft safety is now or it was only that dangerous for a relatively short period of time.

Is the safety of spacecraft travel going to improve? Don't look to NASA Space Shuttle contractor Boeing for leadership in spacecraft safety improvements.

"I expect the shuttle will fly another 20 years," said Rick Stephens, vice president and general manager of Boeing's Homeland Security and Services and Integrated Defense Systems.

Imagine another 20 years of space travel that is 4 orders of magnitude more dangerous than air travel. Boeing would be happy to keep getting paid to maintain the dangerous Space Shuttle for that long. Any reason to develop a more technologically advanced, cheaper, more reliable, and safer alternative? Why do that as long as the current dangerous unreliable obsolete system is generating a large revenue stream?

But Stephens, who has headed up operations in Boeing's Space and Communications Services and Reusable Space Systems, said he did not think the tragedy would speed up the search for alternatives to the shuttles.

How about at least saying that the latest tragedy should be a wake-up call that we should start working on a better design? The Shuttle should be treated as a means to an end rather than a glorious end in itself. That end should be the a continuing improvement in the ability to move humans into space. The Space Shuttle is irrelevant to that goal. An extremely dangerous, unreliable, expensive (all by the standards of the commercial aircraft industry of 65 years ago) launch system built with early 1970s technology that costs $500 million per trip is going to ensure that human presence in space remains a rarity.

Why have the Space Shuttle? What do we need it for? NASA says we need it for the International Space Station. But the International Space Station has been so scaled back in capabilities that it can do very little science. Without the ISS to give the Shuttle a purpose is the Shuttle worth operating?

The Shuttle has been used for upgrades to Hubble. But absent the Shuttle as a repair device a replacement for the Hubble could have been built. That would have cost more than than sending up the Shuttle to do a repair. But at $500 million per Shuttle mission its not cheap. The money saved by occasionally doing Hubble repairs and upgrades is hardly justification for keeping the Shuttle around. If no money was spent on the Shuttle at all then the amount saved could pay for many Hubbles.

There is also the age of the Shuttles from the standpoint of on-going maintenance. The fleet is way older than its designers expected it to get. Parts are hard to find.

The fleet - 22 years old - has now been flying for twice as long as its builders first envisioned. Some parts were made so long ago that they are no longer available. Shuttle engineers have had to turn to Internet auction site eBay for desperately needed hardware and electronics.

Where should we go from here? Science fiction writer Jerry Pournelle has a discussion going about Single Stage To Orbit (SSTO) vehicles. Jerry's message is pretty simple. Instead of operating old technology we should build lots of experimental designs to test out various concepts and see what works, what doesn't, and why.

Two stages to orbit, or one stage and a flyable zero which may well be a ring of jet engines, is another possibility: again the operations penalties are not insignificant. The operational penalties are not small: imagine if every time you wanted to fly across the Atlantic, you had to have a second airplane that did nothing but get your plane aloft. It may be required, but it's not desirable.

So: let me sum it up. We need to build more rocket ships. We need to fly more rocket ships. We need better data. These were conclusions we sent to the President in 1983, and repeated to a different President in 1989. They haven't changed. We need X programs. Real ones, not corporate welfare programs like the "X"-33.

What is more important? Is it more important to use expensive old technology so that we can have humans in space in the short to medium term? Or is it more important to experiment and try out lots of engineering experiments for different approaches for spacecraft designs? Do we want to innovate? Do we want to advance? For the amount of money that is going into keeping the old tech Space Shuttle going and to build an incredibly expensive low scientific value space station we could be designing and trying out many innovative spacecraft designs.

Our old space launch technology is woefully inadequate. Compared to aircraft technology it becomes clear just how unsafe, unreliable, and costly our space launch technology really is. Lots of incremental improvements to an old design will not get us very far. If we want to go into space in a serious manner then we need to admit our mistake in funding the old technology for as long as we have. It's time to move on. Its time to let go of the past. Start concentrating on finding the technologies we need for the future.

Update: Jay Manifold has a bit more info. Also, an earlier post of his points out the low science value of both the Space Shuttle and the ISS. This is something I intend to explore at greater length in future posts. Look at the NSF budget and what it buys in the way of scientific advance. The Jerry Pournelle link above has a quote that the NSF budget at 5 billion dollars per year is half what the Shuttle plus ISS are going to cost per year to operate (supposedly $10 billion - need to search out some details on this). The ISS is going to have one guy on it doing science part time. The amount of science that could be accomplished if that money was spent in other ways (e.g. just give it to the NSF and thereby triple the NSF's budget) could be enormous.

The ISS is not for science. Its purpose is to make people feel good that there are people up there working in space. It accomplishes very little beyond that except for giving aerospace companies multi-billion dollar contracts that stretch out for decades. If we want to do science in space then the money would be far better spent on unmanned probes and satellites. If we want to do human exploration of space then the money would be far better spent on developing next generation launch vehicles and also nuclear thermal propulsion systems. NASA's manned space budget of billions of dollars per year is yielding precious little in science and precious little in technological advances that could lower the cost and increase the safety of human space travel.

If it hasn't yet become clear that I think that the International Space Station and Space Shuttle are monumentally stupid wastes of money then let me make it clear: the International Space Station and Space Shuttle are monumentally stupid wastes of money.

By Randall Parker    2003 February 05 11:16 PM   Entry Permalink | Comments (11)
2003 February 02 Sunday
What NASA Ought To Do

NASA should cancel the Space Shuttle. It is old technology. It is very expensive to operate. It has many safety and reliability problems that are inherent in its design. It is not the future. Its main advantage is that it lets NASA put people up into space now. Its a short-term photo op generator. It lets current generation astronauts go into space. But the Shuttle does not accelerate the human migration into space. By sucking money away from development of newer enabling technologies the shuttle slows the human movement into space.. If the Shuttle had been cancelled after the first accident and if the money spent on it had been spent on new space technologies we'd be much farther along than we are now.

Along with a cancellation of the Shuttle NASA should mothball the space station. Send up a rocket to put the ISS into a higher mothball orbit where it won't decay and enter the Earth's atmosphere for years. Then go back to the basics of working on next generation space travel technology.

NASA has spent the last couple of decades using a launch technology that was a major compromise over initial shuttle design goals. The compromise was adopted because a more ambitious design was going to cost more than Congress would allocate. Instead of delaying or taking longer to develop a great shuttle NASA chose to develop a lousier shuttle. We've now spent two decades funding its higher operating costs and suffering the consequences of its less safe and less dependable design.

NASA should design and build a next generation shuttle. That next generation shuttle ought to be launchable from more than one existing rocket design. Uncouple the shuttle design from the rocket launch design. Also, it should be extremely safe. Instead of a cheaper tile design an inherently tougher cast metal alloy or newer material design should be pursued. The next generation shuttle should be an inherently safer design. It should be capable of saving the passengers even if the booster rocket launching it fails. It also should be capable of landing on and floating in the ocean if a rocket launcher fails.

NASA should work on a faster way to move between planets. Therefore NASA should develop nuclear themal propulsion. A trip to Mars with chemical rocket technology is a bad idea because it would take too long, be too risky, and cost too much. Its long term effect would be similar to that of the Apollo program. The Apollo moon program was a stunt which was pursued in a way that did not lay firm technological foundations that would lower the longer term costs of going back to the moon repeatedly. So once the stunt had been done people lost interest in it and the money needed to keep using its high cost method of getting to the moon dried up. To repeat that same pattern with a Mars shot would be a similar waste of resources. Development of enabling technologies should be placed ahead of performing stunts.

The focus of NASA should shift away from generating short-term results and toward advancing our underlying technologies for going into and operating in space. NASA should not send people into orbit just to have people in orbit. NASA should not try to go to another planet just to be the first to get there. The desire to do manned expeditions should take a backseat to the need to develop technologies that make manned expeditions easier to do.

Update: Jim Miller links to some articles about why the Space Shuttle ought to be cancelled. Says Jim:

The shuttle is too large for people, too small for cargo, underpowered for many tasks, far too expensive, and too dangerous for routine use. The flaws are not fixable with minor design changes, since the basic system design is wrong.

In the face of these obvious truths about what is unfixably wrong with the Shuttle the Shuttle program has been kept running for decades. It is time to stop being sentimental about the Space Shuttle just because it takes humans into space. It kills people. Its unreliable. Its extremely cost. Its doing precious little to advance space science and space technology. It takes money away from the development of approaches that could really advance our abilities to do things in space.

While Gregg Easterbrook gets some technical facts wrong he's right in arguing that the Shuttle has been kept alive by lobbying of aerospace companies and Congresscritters protecting jobs for their districts. We should not be fooled and let patriotic emotional appeals blind us to the economic and political interests that work to protect an economic and technological albatross.

Switching to unmanned rockets for payload launching and a small space plane for those rare times humans are really needed would cut costs, which is why aerospace contractors have lobbied against such reform. Boeing and Lockheed Martin split roughly half the shuttle business through an Orwellian-named consortium called the United Space Alliance. It's a source of significant profit for both companies; United Space Alliance employs 6,400 contractor personnel for shuttle launches alone. Many other aerospace contractors also benefit from the space-shuttle program.

Easterbrook is quite right when he argues that we should abandon the International Space Station and stop putting humans up into orbit while we develop better technologies for doing so. The ISS costs billions and produces precious little in the way of scientific advances. The $35 billion spent on it so far would have paid for a lot of nanotechnology research. Nanotech promises to reduce the costs of manufacturing space vehicles by orders of magnitude. We should stop pouring money down holes and instead work on making the advances that will make a future in space possible.

Update II: I've previously posted links to articles that claimed nuclear electric propulsion was suitable for space probes but that nuclear thermal propulsion would be better for human space travel. But Jay Manifold says nuclear electric is the way to go. Also see this previous post by Jay. Jay knows a lot more about this than I do and I take his word for it. In any case, some form of nuclear propulsion is what we need to develop for human travel between planets in the solar system. The development of nuclear propulsion technology is just one of the things that would become possible if the money now going for the Space Shuttle and ISS was rechanneled toward developing new technologies for space launch and space travel.

By Randall Parker    2003 February 02 08:39 PM   Entry Permalink | Comments (5)
2003 February 01 Saturday
Weather Radar Track Of Columbia Shuttle Debris

Blogger John Moore has posted a link to a weather radar track of the shuttle debris.

I hope this tragic loss causes a reassessment of the shuttle program. Its a lousy old tech design that was a poor choice to begin with. We need a radically newer human launch vehicle design that is inherently much safer and lower maintenance.

Here's a Google News news article cluster on the loss of the Columbia. Here are two more here and here.

Update: A friend points out that the Shuttle could have been damaged in orbit by collision with a small fragment of space debris. Space debris is a growing problem. Tethers that ride magnetic fields to slowly change orbits have been proposed as a way to clean up space debris. But one has to ask: Even if such a system was launched can really small orbiting fragments be identified in the first place? Surely larger sized pieces can be tracked. But can the smallest fragment that can cause lethal damage to a shuttle be identified with radar or opticals sensor systems? I'm guessing that the answer is no. Anyone know?

By Randall Parker    2003 February 01 10:44 AM   Entry Permalink | Comments (1)
2003 January 19 Sunday
Bush May Announce Nuclear Rocket Trip To Mars

President Bush may announce an aggressive project for a nuclear powered spaceship to make a manned mission to Mars.

President George Bush may announce the plan, named Project Prometheus, at his State of the Union address on January 28, according to a report in the Los Angeles Times. It would commit the US to the exploration of Mars as a priority and herald the development of a nuclear-powered propulsion system. The first voyage could take place as soon as 2010.

"We're talking about doing something on a very aggressive schedule to not only develop the capabilities for nuclear propulsion and power generation but to have a mission using the new technology within this decade," said Nasa administrator Sean O'Keefe.

The most gratifying aspect of this proposal is the underlying attitude at NASA that is driving the nuclear propulsion approach. NASA has spent the last couple of decades trying to patch up yesterday's technology (the loser space shuttle) rather than try to make technological leaps that would make space exploration more affordable and feasible. Now NASA wants to work on enabling technologies.

The new rocket proposal also represents a significant change at the agency, which has typically been driven by a quest to get somewhere -- the moon, Mars or the outer planets in the solar system -- and then developed the technologies to do so.

Instead, O'Keefe has begun shifting the agency's focus to developing so-called "enabling technologies" to carry out missions whatever they might be.

NASA is now denying that Project Prometheus will be announced in the President's State of the Union address. But NASA may be backpedalling in order to allow the President to make the official announcement.

"At this point I can't say what they plan beyond what we announced in the 2003 budget," Savage said.

"O'Keefe didn't say that there would be announcement in the State of the Union concerning NASA. He doesn't know what's going to be in the State of the Union and certainly wouldn't get out in front of the President," Savage responded to SPACE.com.

This is not as sudden a decision as it might seem. NASA decided to reactivate its nuclear propulsion program a year ago.

ALBUQUERQUE, NEW MEXICO – For the first time in a decade, NASA has been given the go-ahead to say the “N” word – nuclear power for space.

The White House-backed NASA budget for fiscal year 2003 includes a major nuclear systems initiative that sets the stage for faster trip times by spacecraft exploring the solar system and powering human outposts on distant worlds.

If a nuclear propulsion program is going to be used to go somewhere the logical first stop is obviously Mars. Serious discussions in NASA of a nuclear propulsion mission to Mars were reported by Space.com to have started back in 2000.

In the past few months, several NASA notables, including associate administrators Joe Rothenberg and Gary Payton, have mentioned publicly that nuclear power in space transportation deserves a closer look. The comments indicate that if public relations efforts can gain acceptance for the possibility, future interplanetary missions may include nuclear-power options.

The NASA proposal is not for a rocket that a series of nuclear explosions made behind a shield on the back of the spacecraft (ala Niven and Pournelle's Footfall). Rather, the idea is to use a nuclear reactor to heat hydrogen propellant and then expel it behind the spacecraft at a high velocity.

In NTP, a compact lightweight nuclear reactor heats hydrogen propellants to a high temperature, e.g., 3000 K. Because the molecular weight of hydrogen is almost a factor of 10 smaller than the molecular weight of hydrogen/oxygen combustion products, the exhaust velocity of hot hydrogen propellant is much greater than that of hydrogen/oxygen. A NTP engine can achieve a hydrogen exhaust velocity of 10 kilometers/sec. and a maximum Delta-V increase in rocket velocity of ~22 kilometers/sec.

Also see this previous post in nuclear powered spaceships.

Update: Bruce Moomaw has written a follow-up article in SpaceDaily.com claiming that Peter Pae of the Los Angeles Times confused talk of a Nuclear Electric Propulsion system for space probes with a much more expensive and longer term development effort needed to build a Nuclear Thermal Propulsion system for a human trip to Mars program.

Peter Pae, in his Times article, seems to have been completely confused by O'Keefe's references to the fact that such a vastly larger nuclear-rocket system could indeed send a manned ship to Mars in only a couple of months, and so falsely connected them to O'Keefe's simultaneously declared indications that the Bush Administration does intend to considerably increase the current spending level on the NEP program while renaming it "Prometheus".

At this point it sounds like Bush will not announce a Mars mission or even the development of a nuclear propulsion system for a Mars effort. Instead the Bush Administration is going to increase funding for a nuclear propulsion system more suited for space probes. This will allow the development of much more ambitious unmanned space exploration missions. But its not going to enable the development of a spacecraft that can make a faster trip to Mars.

Update II: Bill Emrich of NASA Marshall Space Flight Center is proposing a way to make a fusion reactor (as compared to the fission reactor designs proposed for NTP and NEP designs mentioned above) for spacecraft propulsion.

Emrich is proposing a bold solution. He wants to use microwaves to heat the plasma to 600 million kelvin, triggering a different kind of fusion reaction that generates not neutrons but charged alpha particles - helium nuclei. These can then be fired from a magnetic nozzle to push the craft along.

If NASA wants to advance the state of technology for doing manned spaceflight then the development of more advanced propulsion systems should be at the top of its list of priorities. If it was up to me I'd axe the International Space Station and the Shuttle and take all the money being spent on them and spend that money on the development of nuclear fission and fusion propulsion systems. In the short term less would be accomplished in space. We'd have fewer news events with video of astronauts floating around in and outside of space structures. But NASA is accomplishing very little in either science or in technological advance with its current efforts. Rather than spend so much doing so little with yesterday's technologies NASA ought to take bigger steps and choose long term payoffs over short-term photo-ops.

By Randall Parker    2003 January 19 09:59 AM   Entry Permalink | Comments (5)
2003 January 17 Friday
Tethers As Orbital Space Debris Cleaners

It is very expensive to launch propellants into orbit. So it would be prohibitively expensive for a spacecraft to move around in orbit to pick up space junk. Similarly, it would be too expensive to give each launched satellite enough propellant to deorbit itself at the end of its service life. However, a propellant-free way of moving objects around in orbit very slowly is under development. How a long tether propulsion system moves around in orbit:

It works as a thruster because a magnetic field exerts a force on the current-carrying wire. When electrical current flows through a through a tether connected to a spacecraft, the force exerted on the tether by the magnetic field raises or lowers the orbit of the satellite, depending on the direction the current is flowing. The current is extracted from the magnetic field of the Earth's ionosphere by the tether.

"The working principle of electrodynamic tethers is not new, but the application to space transportation will be revolutionary," said Les Johnson, principal investigator of the ProSEDS experiment. "Imagine driving your car and never having to stop for gas - that's what a tether does for a spacecraft in low-Earth orbit. Tether propulsion requires no fuel, is completely reusable and environmentally clean, and provides all these features at low cost."

There are a lot of small fragments flying around in low earth orbit. The number of fragments is growing in number and as they do they collide more often with satellites. Those collisions break pieces off of satellites and hence create new fragments that in turn can collide with still other satellites. Joseph Carroll of Tether Applications has proposed the use of space tethers as a cost effective way to collect up loose fragments in orbit.

His plan is to equip the tether with a roving sheepdog, a small vehicle that is released near a piece of debris to fly around it looking for a suitable point to latch onto. Once attached, it returns to the tether with its prize in tow. The tether then heads for another piece of junk and sets the sheepdog loose again. "A single tether could be reused up to 100 times, capturing a piece of junk many times its own mass each time, " he says.

The NASA ProSEDS project will soon test the first tether propulsion system.

The Propulsive Small Expendable Deployer system - called ProSEDS - is a tether-based propulsion experiment that draws power from the space environment around Earth, allowing the transfer of energy from the Earth to the spacecraft.

Inexpensive and reusable, ProSEDS technology has the potential to turn orbiting, in-space tethers into "space tugboats" -- replacing heavy, costly, traditional chemical propulsion and enabling a variety of space-based missions, such as the fuel-free raising and lowering of satellite orbits.

The flight of ProSEDS, scheduled for early in 2003, will mark the first time a tether system is used for propulsion. To be launched from the Cape Canaveral Air Force Station, Fla., ProSEDS will fly aboard an Air Force Delta II rocket and demonstrate an electrodynamic tether's ability to generate significant thrust.

"We achieved an important milestone with our tests in November," said ProSEDS project manager Leslie Curtis of the Marshall Space Flight Center's Space Transportation Directorate. "Using a vacuum chamber to represent the space environment, we successfully simulated the first 16 hours of the experiment's initial flight."

In orbit, ProSEDS will deploy from a Delta-II second stage a 3.1-mile-long (5 kilometers), ultra-thin bare-wire tether connected with a 6.2-mile-long (10 kilometers) non-conducting tether. The interaction of the bare-wire tether with the Earth's magnetic field and the ionosphere will produce thrust, thus lowering the altitude of the stage.

Although the mission could last as long as three weeks, the first day is the most critical, because the primary objective of demonstrating thrust with the tether should be achieved during the experiment's first 24 hours.

Tethers also look like a promising way to deorbit old satellites.

The Terminator Tether™ (TT) system will provide a lower mass and more reliable means of bringing old satellites out of orbit. The TT system will be a small package bolted onto the satellite. When the end of the satellite's useful life is reached, the TT system will deploy a several-kilometer length of conducting tether from the satellite. Because the satellite and tether are moving at great speed across the Earth's magnetic field, a voltage will be induced along the tether. This voltage will cause a current to flow along the tether. At the ends of the tether, the current will be transmitted to the thin space plasma present in low-Earth orbit.

The current flowing through the tether will cause power to be dissipated in the resistance of the metal in the tether. This power has to come from somewhere, and it comes out of the orbital energy of the satellite. As a result, the orbit of the satellite decays, and this decay can be very rapid. Calculations indicate that a tether massing as little as 2% of the satellite mass can bring a satellite out of some orbits in just a few weeks (compared to centuries without the Terminator Tether™).

The Tethers Unlimited Inc. Terminator Tether™does not require any propellant.

The Terminator Tether™ is a small device that uses electrodynamic tether drag to deorbit a spacecraft. Because it uses passive electromagnetic interactions with the Earth's magnetic field to lower the orbit of the spacecraft, it requires neither propellant nor power. Thus it can achieve autonomous deorbit of a spacecraft with very low mass requirements.

The tether is necessary because parking old satellites in "graveyard" orbits eventually results in the generation of smaller and more dangerous pieces of space debris as micrometeorites collide with the satellites.

Some organizations are currently planning on boosting their satellites to higher, "graveyard" orbits at the end of their missions. This also requires that the satellite's power, propulsion, and guidance be working at the end of the satellite's mission. Moreover, it doesn't really solve the problem - it just delays it, somewhat like a toxic waste dump. Recent studies have shown that satellites left in a higher graveyard orbit will slowly break apart as micrometeorites hit them, and the smaller fragments will filter back down to lower altitudes [2]. Thus satellites boosted to higher disposal orbits will eventually endanger operational satellites. Moreover, once the old satellites fragment into smaller particles, it will be nearly impossible to clean up the debris. Consequently, it will be much more cost effective in the long run to deal with the problem properly from the start, and deorbit all old spacecraft, rather than leaving them as a problem for our children to deal with.

Tethers are not going to exert a lot of force. Orbits will change only very slowly. But there's no rush when the cargos are under automated controls and there are no living passengers.

By Randall Parker    2003 January 17 07:22 PM   Entry Permalink | Comments (0)
2002 October 23 Wednesday
Dust Discs To Discover Planets Around Other Stars

Planets create characteristic dust patterns around stars:

The new technique, pioneered by University of Rochester astronomer Alice Quillen and graduate student Stephen Thorndike and described in the current issue of The Astrophysical Journal Letters, instead is based on studies of patterns in dust discs associated with planet-bearing stars.

By Randall Parker    2002 October 23 10:56 PM   Entry Permalink | Comments (0)
2002 September 25 Wednesday
Moon microsatellites for $15 million per mission

The article also makes an argument for returning to the moon. It could be done for a very small fraction of the cost of a Mars trip. Click thru to the second page of the article for details. While NASA wastes large amounts of money on other projects at least the military is working to get more information about the moon:

"The DoD is embarking on a rather major program to develop technologies for microsatellites and the ability to get them into space," said U.S. Air Force Brigadier General Simon Worden, deputy director of operations for the U.S. Space Command at Peterson Air Force Base in Colorado. Several small satellites could be directed to the Moon, to orbit well as land on it. Such an effort could be accomplished in a few years time, Worden said.

These ultra-small spacecraft would ride their way into geosynchronous transfer orbit as a secondary payload on some craft with another primary mission. The tiny probes would then make a propulsive beeline to the Moon. Trip time to the Moon: some 97 days.

By Randall Parker    2002 September 25 12:18 PM   Entry Permalink | Comments (0)
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