My recent few days absence here was due to attendance at a recent Liberty Fund conference on liberty, biological determinism and Steven Pinker's The Blank Slate: The Modern Denial of Human Nature. The conference was also attended by bloggers Alex Tabarrok and Tyler Cowen of Marginal Revolution, the mentally nimble and facially expressive (really, his speedily changing mental state is visible for all to see) Daniel Drezner (see Dan's own description of the conference's highlights), the towering intellectual figure Megan McArdle and heck-of-a-nice-guy art dealer and historian David Nishimura.
One very gratifying moment at the Liberty Fund conference came when Ph.D. academic economists Alex and Tyler both emphatically agreed with me that spending on the search for asteroids that might strike the Earth is a woefully underfunded public good. Well, that leads to the topic for this post. One big asteroid hit could ruin your whole day and even end your life along with the lives of hundreds of millions or billions of others. I don't want to wake up some day and hear a news report that we all have about 3 days to live because of a just-discovered asteroid that is about to kill us all that can not be stopped because we didn't prepare in advance.
Former NASA astronaut Russell L. "Rusty" Schweickart is currently Chairman of the B612 Foundation which is dedicated to the development of anti-asteroid defenses to protect planet Earth from Near Earth Asteroids (NEAs). The U.S. Senate Subcommittee on Science, Technology, and Space held hearings on April 7, 2004 about Near Earth Objects (NEO) which included discussion of what should be done about asteroids that may strike planet Earth. Schweickart recently testified before those hearings presenting arguments on the feasibility and desirability of developing a system for diverting any large asteroid found to be on a collision course with Earth.
It became immediately clear to us that the combination of advanced propulsion technologies and small space qualified nuclear reactors, both operating in prototype form already, would be powerful enough, with reasonable future development, to deflect most threatening asteroids away from a collision with the Earth, given a decade or more of advance warning.
Nevertheless we saw two immediate problems.
First we lack the specific knowledge of the characteristics of NEAs necessary to design anything approaching a reliable operational system. We could readily show that the technology would exist within a few years to get to and land on an asteroid. We also determined that after arriving at the asteroid we would have enough propulsive energy available to successfully deflect the asteroid from an Earth impact a decade or so later. What was missing however was knowledge about the structure and characteristics of asteroids detailed enough to enable successful and secure attachment to it.
Second we recognized that before we would be able to gather such detailed information about NEAs there would likely be many public announcements about near misses and possible future impacts with asteroids which would alarm the general public and generate a growing demand for action. We felt strongly that there needed to be some legitimate answer to the inevitable question which will be put to public officials and decision makers, "and what are you doing about this?"
These two considerations led us to the conclusion that the most responsible course of action would be to mount a demonstration mission to a NEA (one of our choosing) which would accomplish two essential tasks; 1) gather critical information on the nature of asteroid structure and surface characteristics, and 2) while there, push on the asteroid enough to slightly change its orbit thereby clearly demonstrating to the public that humanity now has the technology to protect the Earth from this hazard in the future.
We furthermore determined that this demonstration mission could be done with currently emerging capabilities within 10-12 years.
We therefore adopted the goal of "altering the orbit of an asteroid, in a controlled manner, by 2015".
Astronaut Edward Lu, President of the B612 Foundation also testified at the Senate hearings arguing for
Recent developments have now given us the potential to defend the Earth against these natural disasters. To develop this capability we have proposed a spacecraft mission to significantly alter the orbit of an asteroid in a controlled manner by 2015.
Why move an asteroid? There is a 10 percent chance that during our lifetimes there will be a 60 meter asteroid that impacts Earth with energy 10 megatons (roughly equivalent to 700 simultaneous Hiroshima sized bombs). There is even a very remote one in 50,000 chance that you and I and everyone we know, along with most of humanity and human civilization, will perish together with the impact of a much larger kilometer or more sized asteroid. We now have the potential to change these odds.
There are many unknowns surrounding how to go about deflecting an asteroid, but the surest way to learn about both asteroids themselves as well as the mechanics of moving them is to actually try a demonstration mission. The first attempt to deflect an asteroid should not be when it counts for real, because there are no doubt many surprises in store as we learn how to manipulate asteroids.
Why by 2015? The time to test, learn, and experiment is now. A number of recent developments in space nuclear power and high efficiency propulsion have made this goal feasible. The goal of 2015 is challenging, but doable, and will serve to focus the development efforts.
How big of an asteroid are we proposing to move? The demonstration asteroid should be large enough to represent a real risk, and the technology used should be scaleable in the future to larger asteroids. We are suggesting picking an asteroid of about 200 meters. A 200 meter asteroid is capable of penetrating the atmosphere and striking the ground with an energy of 600 megatons. Should it land in the ocean (as is likely), it will create an enormous tsunami that could destroy coastal cities. Asteroids of about 150 meters and larger are thought to be comprised of loose conglomerations of pieces, or rubble piles, while smaller asteroids are often single large rocks. The techniques we test on a 200 meter asteroid should therefore also be applicable to larger asteroids.
Lu argues that the nuclear propulsion system proposed for the Jupiter Icy Moons Orbiter spacecraft should be used to move an asteroid.
How can this be accomplished? This mission is well beyond the capability of conventional chemically powered spacecraft. We are proposing a nuclear powered spacecraft using high efficiency propulsion (ion or plasma engines). Such propulsion packages are currently already under development at NASA as part of the Prometheus Project. In fact, the power and thrust requirements are very similar to the Jupiter Icy Moons Orbiter spacecraft, currently planned for launch around 2012. The B612 spacecraft would fly to, rendezvous with, and attach to a suitably chosen target asteroid (there are many candidate asteroids which are known to be nowhere near a collision course with Earth). By continuously thrusting, the spacecraft would slowly alter the velocity of the asteroid by a fraction of a cm/sec – enough to be clearly measurable from Earth.
I have previously argued that the development of nuclear ion propulsion for the JIMO mission is an excellent idea. Well, development of a space nuclear propulsion system for any number of missions is a great idea because it then allows the propulsion system to be used on something that may some day save millions or perhaps even billions of lives. The development of a space nuclear propulsion system ought to be greatly accelerated so that we have a method to protect us against asteroids as soon as possible.
Encouragingly the Bush Administration has allocated $3 billion over the next 5 years for Project Prometheus. NASA has more on Prometheus.
Aside from still moving too slowly to develop technologies to use against an asteroid that is on a collision course there is still one big problem with NASA's current strategy: the amount of money going into finding asteroids on a collision course with Earth is still chump change.
NASA spends a modest $3.5 million per year as part of the Spaceguard Survey search for large asteroids, the sort that could cause global damage, including a global "winter" that might last years and could kill off some species and possibly threaten civilization.
The current mission of the NASA Near-Earth Object Program is focused on finding only the bigger asteroids and not even all of them.
NASA’s Near-Earth Object Program Office will focus on the goal of locating at least 90 percent of the estimated 2,000 asteroids and comets that approach the Earth and are larger than about 2/3-mile (about 1 kilometer) in diameter, by the end of the next decade.
“These are objects that are difficult to detect because of their relatively small size, but are large enough to cause global effects if one hit the Earth,” said Dr. Donald K. Yeomans of JPL, who will head the new program office. “Finding a majority of this population will require the efforts of researchers at several NASA centers, at universities and at observatories across the country, and will require the participation by the international astronomy community as well.”
A panel of experts working at NASA's request has recommended a bold new search for potentially dangerous asteroids, including smaller objects that could cause regional damage in an Earth impact.
The price tag: At least $236 million.
The United States is spending hundreds of billions in Iraq for unclear benefit. The US government spends billions on many other undertakings of questionable benefit. In the space program both the Space Shuttle and the International Space Station come to mind as programs with dubious benefits and huge price tags. By contrast, we know that somewhere out there multiple asteroids are on collision paths with planet Earth and some are large enough to kill millions or billions of lives. Efforts to discover them and plot their orbits will both help to protect human lives and further the advance of space science. Efforts to develop technologies to deflect asteroids will both protect human lives and increase our capabilities to do things in space for other purposes. The effort to discover and plot the future trajectories of all asteroids ought to be increased by a couple of orders of magnitude and considerable funding should be allocated to the development of spacecraft capable of deflecting asteroid paths.
Update: Tyler Cowen draws my attention to a previous report he linked to from the Volokh Conspiracy about an effort to provide monetary incentives for private individuals and groups to discover asteroids.
"Amateur astronomers could receive awards of $3,000 for discovering and tracking near-Earth asteroids under legislation approved by the House of Representatives on Wednesday.
"Given the vast number of asteroids and comets that inhabits Earth's neighborhood, greater efforts for tracking and monitoring these objects are critical," said Rep. Dana Rohrabacher, sponsor of the legislation that passed 404-1.
Rohrabacher's legislation is H.R. 912, the Charles "Pete" Conrad Astronomy Awards Act.
H.R. 912, the Charles "Pete" Conrad Astronomy Awards Act, named for the third man to walk on the moon, establishes awards to encourage amateur astronomers to discover and track near-earth asteroids. The bill directs the NASA Administrator to make awards, of $3,000 each, based on the recommendations of the Smithsonian Minor Planet Center. Earth has experienced several near misses with asteroids that would have proven catastrophic, and the scientific community relies heavily on amateur astronomers to discover and track these objects.
There is a US Senate equivalent of that bill as S. 1855 for the 108th Congress. However, it is sitting in the Senate Committee on Commerce, Science, and Transportation. This bill deserves more attention.
Tyler also links to a Gregg Easterbrook Easterblogg post on how the threat from asteroids is, statistically speaking, roughly the same as that posed by commercial airliner risks.
Should humanity simply assume its luck will hold? Many don't think so. As Nathan Myhrvold, the chief technology officer at Microsoft, has written, "Most estimates of the mortality risk posed by asteroid impacts put it at about the same risk as flying in a commercial airliner. However, you have to remember that this is like the entire human race riding the plane."
Here is a potentially huge threat that could be protected against at a cost that probably ranges in the billions or at most a few tens of billions of dollars. In the process of developing the knowledge and technology needed to protect against it we will both gain scientific knowledge about the solar system and will gain technologies that are useful for doing other things up in space. Contrast the cost and benefit of doing this with the cost of the International Space Station which has costs for US taxpayers alone that many estimate to be as high as $100 billion if not more (also see here and here for more estimates in the $100 billion range). The ISS accomplishes very little in terms of science produced. An asteroid protection program might literally save all our lives. The risk is high enough to justify expenditures to protect us.
|Share |||Randall Parker, 2004 April 16 03:41 PM Dangers Natural General|