2011 July 09 Saturday
Value Of Space Shuttle Questioned

John M. Logsdon, a member of the 2003 Columbia Accident Investigation Board, ays it is doubtful that the US Space Shuttle was worth the money spent on it.

But were these considerable benefits worth the $209.1 billion (in 2010 dollars) that the program cost? I doubt it. The shuttle was much more expensive than anyone anticipated at its inception. Then-NASA administrator James Fletcher told Congress in 1972 that the shuttle would cost $5.15 billion to develop and could be operated at a cost of $10.5 million per flight. NASA only slightly overran development costs, which is normal for a challenging technological effort, but the cost of operating the shuttle turned out to be at least 20 times higher than was projected at the program's start.

The Shuttle came nowhere close to the cheap space bus image used to promote its construction.

The Columbia Accident Investigation Board (CAIB) found that the technical goals of the Shuttle made it riskier to operate than a design with more limited objectives.

It is the Board's view that, in retrospect, the increased complexity of a Shuttle designed to be all things to all people created inherently greater risks than if more realistic technical goals had been set at the start. Designing a reusable spacecraft that is also cost-effective is a daunting engineering challenge; doing so on a tightly constrained budget is even more difficult. Nevertheless, the remarkable system we have today is a reflection of the tremendous engineering expertise and dedication of the workforce that designed and built the Space Shuttle within the constraints it was given.

In the end, the greatest compromise NASA made was not so much with any particular element of the technical design, but rather with the premise of the vehicle itself. NASA promised it could develop a Shuttle that would be launched almost on demand and would fly many missions each year. Throughout the history of the program, a gap has persisted between the rhetoric NASA has used to market the Space Shuttle and operational reality, leading to an enduring image of the Shuttle as capable of safely and routinely carrying out missions with little risk.

General rocket failure rates are so high that manned flight needs capsules or small spacecraft for humans that can survive failure of rockets.

But with the end of the Shuttle program we lose some capabilities. James Oberg points to a half dozen capabilities unique to the shuttle.

By Randall Parker    2011 July 09 11:41 PM   Entry Permalink | Comments (17)
2011 February 16 Wednesday
Lasers To Accelerate Rockets?

The problem with chemical rockets is that most of their fuel basically lifts other fuel. So the rocket fuel burns to lift fuel so it can burn to life other fuel so it can burn. Chemical rockets have a pathetically low payload to fuel ratio. Cheap cargo lift into space has to involve avoiding the need to carry all that fuel.

Overcoming gravity is not easy. Conventional rockets are 97 percent fuel and tanks. Even NASA's mighty Saturn 5 moon launchers had just 3 to 5 percent available for payloads.

NASA wants to send the energy up to a rocket using lasers as it ascends.

A new technology under study would use ground-based lasers or microwaves to zap a heat exchanger on the rocket, releasing more energy from the fuel. The heat exchanger works like a hot plate, spiking the temperature of the fuel to more than 3,100 degrees Fahrenheit (1,704 degrees Celsius), which significantly increases the rocket's thrust.

I've read similar proposals for powering vehicles designed to travel up nanotube beanstalks into orbit. These vehicles would be like elevators that would have their own motors for moving them up. They would need power to lift cargo. Either the beanstalk would need a superconducting cable to carry electric power to the elevators or lasers would need to be aimed at the elevator car. One way of using the power in that case would be via photovoltaics to convert it into electricity. Though the PV adds weight.

A third possibility for cheaper space launch would be extreme acceleration of a cargo (said acceleration would only work for non-living cargo) in a tunnel or mountain side accelerator to impart all needed lift before the cargo even enters the atmosphere. Again, the need to carry fuel would be avoided.

The beanstalk approach takes too much time for humans. The ground-based accelerator causes g forces too high for humans to withstand. So the laser approach aimed at rockets might some day turn out to be the cheap way to put humans into orbit. Their cargo can get shipped separately using the other two approaches.

By Randall Parker    2011 February 16 10:49 PM   Entry Permalink | Comments (24)
2010 January 19 Tuesday
Buy A Used Space Shuttle $28.2 Million Each

These babies are priced to move and won't last long.

The space agency announced late last week it has dropped the sale price of a used space shuttle from $42 million to the bargain-basement price of $28.8 million. With NASA moving to retire the space shuttle fleet this fall, the agency is looking to move a few shuttles and bring in some much-needed cash.

When I look at the NASA space shuttles I see really bad design choices made in the 1970s and kept alive for a few decades at taxpayer expense. They were never leading edge technology. Putting humans together with cargo was a fundamental mistake. The design put humans at higher risk (with fatal results) while requiring higher than necessary safety standards for cargo that made the cargo expensive to put into space.

A bad safety culture at NASA made the risks even greater. Politicos kept the shuttle alive because lots of rubes thought they were seeing really great technology launching people into space. The space shuttle was more about keeping alive a mythology than advancing the state of the possible for a human move into space.

Our greatest hope for lower costs of transportation into low Earth orbit comes from the idea of using a giant beanstalk elevator to move things into space.

By Randall Parker    2010 January 19 11:10 PM   Entry Permalink | Comments (12)
2009 October 25 Sunday
NASA Ares Rocket Development To Take Too Long

An article in New Scientist about the NASA Ares rocket program reports that a White House advisory panel chaired by former Lockheed Martin CEO Norman Augustine recommends against further development of the Ares rocket because it will take too long to develop.

The rocket is set to make its first test flight on 27 October. But the committee believes the rocket will not be ready to loft crew to orbit until 2017, two years after the ISS is scheduled to be abandoned and hurled into the Pacific Ocean, Augustine said. Extending use of the space station to 2020 would not make much difference, since this would eat up funds available for Ares I and delay its first flight to 2018 or 2019, added committee member Edward Crawley of MIT.

What I found most interesting: How can a rocket that is a derivative of the existing Space Shuttle solid rocket booster take, what, 10 years to develop? When did Ares development begin? 2005? 2006? Some of the contracts were announced in 2006 and 2007. So how does it take 10 years to develop a rocket that is, again, a derivative design? Wasn't one of the points of the derivative design that it was more proven and therefore supposedly safer?

Maybe NASA has so little money to spend on it that the development is stretched out with more tasks done in series? As a percentage of GDP NASA's budget is a tenth of what it was in its glory days. Though in inflation adjusted terms the absolute amount of spending decline is not that great.

America pretends to have a serious space program.

By Randall Parker    2009 October 25 12:20 AM   Entry Permalink | Comments (17)
2009 June 20 Saturday
Inflatable Tower Into Space?

New Scientist has a report about a proposal to build an an inflatable tower into space.

Inflatable pneumatic modules already used in some spacecraft could be assembled into a 15-kilometre-high tower, say Brendan Quine, Raj Seth and George Zhu at York University in Toronto, Canada, writing in Acta Astronautica (DOI: 10.1016/j.actaastro.2009.02.018). If built from a suitable mountain top it could reach an altitude of around 20 kilometres, where it could be used for atmospheric research, tourism, telecoms or launching spacecraft.

Supposedly this is buildable from existing materials. Anyone think this could work?

Regards telecoms: My impression (correct me if I'm wrong) is that the spread of fiber optic cable and transmission rate increases of such cable makes satellite comm less important as compared to ground comm than used to be the case. Fiber optic cable is especially important for the internet because it offers lower latencies than satellites. People want their pages painted immediately.

What is the potential for a bigger space industry? The biggest potential I can see: cheap launch for a fleet of solar power satellites. Space manufacturing doesn't seem like a compelling benefit. It is far easier to do manufacturing down here. Whereas cheaper energy strikes me as far more valuable.

By Randall Parker    2009 June 20 04:05 PM   Entry Permalink | Comments (8)
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