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An International Space Scrap-yard

evac and de-orbit coming soon
by Jeffrey F. Bell
Honolulu HI (SPX) Jul 12, 2004
It's time to face the facts about the International Space Station. The ISS is deteriorating so rapidly that there is an excellent chance that it will die before the Space Shuttle is back in service.

Of course the Shuttle RTF date constantly shifts further into the future as NASA engineers continue to bungle the many projects undertaken to meet the CAIB mandates for improved safety. It seems that the Shuttle program no longer has the skills needed even to design a simple rigid extension boom for the Canadarm. And the capabilities of the RCC repair kit seem to get smaller every month.

But even if one believes the mid-2005 date for the resumption of "normal" Shuttle supply flights to the ISS, it becomes increasingly hard to believe that the Station will still be manned at that time, or even stable enough to dock with. People inside the project have been telling me that they expect the crew evacuation to happen within one year. I didn't really believe them until I read a recent piece of investigative journalism by Florida Today. It is clear from the ISS program's own internal documents that the ISS can't be kept alive by Soyuz/Progress during a prolonged Shuttle stand-down.

The basic problem is that major components on the ISS continue to fail at a surprising rate. The Station was designed for a useful life of ten years after completion, so all its components should have been designed to last at least that long. But many key systems are breaking down after only a few years in orbit. Examples include:

+ the 600-lb momentum wheels that control the station's attitude and their control electronics,
+ the spacesuits that are needed to repair the gyros and other external components,
+ the power torque wrenches used to bolt together station components,
+ the treadmill that keeps the crew's muscles and bones from deteriorating too much,
+ the main oxygen generator,
+ the air quality sensors that monitor dangerous contaminants in the ISS atmosphere.
+ the 4 million lines of computer software that has at least 1,000 known bugs

I cannot understand why these vital components are all failing. The ISS was originally designed to have a useful lifetime of 10 years after assembly was completed. Even with the long delays in assembly, most elements of the ISS have been in space less than 5 years. Clearly, a lot of stuff is not meeting specifications.

This situation is even more inexplicable when you consider the excellent record of similar components on unmanned spacecraft. Many satellites have momentum wheels that run continuously to provide fine attitude control, but we never hear of them wearing out (except in the Hubble Space Telescope which was also designed to be maintained by Shuttle). Most have thrusters using hydrazine and nitrogen tetroxide, and they never suffer from the leaks and corrosion that require the Shuttle's thruster modules to be frequently pulled out for repair. And many unmanned spacecraft have been in space much longer than ISS. Cassini/Huygens has been in flight about as long as the first ISS modules, but it is not riddled with similar failures.

I would like to see a detailed engineering explanation of why all these systems on ISS are failing. The possible reasons are all pretty depressing:

A) we don't know how to design gyros, spacesuits, treadmills, air quality sensors etc. that will work reliably for more than 2-3 years;

B) the ISS engineers got lazy with all that potential up- and down-cargo provided by Shuttle/MPLS, and didn't try for reliability;

C) they were under secret orders to make ISS dependent on frequent Shuttle supply missions so that Shuttle flights could be justified after the ISS was completed.

If A) is true, clearly we have no chance of maintaining a manned base on the Moon or Mars where resupply will be less frequent and more expensive than to ISS. If B) and/or C) are the correct explanation; we cannot trust the current staff at NASA to carry out Plan Bush in a timely and cost-effective manner.

A related issue is that too many of these unreliable components are located on the outside of the ISS, where spacewalks are needed for repair or replacement. The electronic modules that control the gyros are an excellent example of this. There's no reason they can't be located inside the pressure hull. Station EVAs were always dangerous because NASA had waived the usual ban on sharp or hot objects on manned spacecraft which could rip or melt holes in the suits. The last three spacewalk attempts on ISS have revealed that the spacesuits on board are deteriorating along with everything else. The caretaker crew had to mix-and-match elements of several suits to produce two that were safe to use.

And many of these components are so large and so heavy that replacements cannot be lifted in Progress or the European ATV vehicle. They can only be ferried up by the Italian-made logistics modules in the Shuttle cargo bay. Down-cargo limitations are even more severe. It was very difficult to find room in a Soyuz return module for a coffee-can-sized atmospheric sampling device that needed to be returned for a contamination check.

And there is the disquieting issue of that loud crunching sound. The first time this occurred, I used it as a hook for a column on the rising menace of orbital debris. But now that the Mystery Sound has been heard at least twice at the same point in the ISS, it is clear that is caused by some defect in some ISS mechanism. This doesn't make the debris problem any less threatening to ISS and future orbital operations (as some ill-informed readers think), but it does indicate that some system on ISS may be tearing itself apart. Extensive investigations have not identified the source of the noise -- so NASA in its usual way assumes that it is something non-vital like a ventilation fan.

The official estimate is that all these accumulating problems add up to a %6/yr chance of catastrophic failure on ISS with a crew on board -- and an incredible %50/yr chance without a crew. These estimates are probably too low, like most NASA risk estimates.

So in the near future, NASA will have to face two difficult decisions: A) to withdraw the crew from ISS (or not replace one when its 6-month deployment ends); B) to execute a controlled deorbit of the 216-ton station into a remote ocean before it falls on a populated area.

The first decision will be very difficult to make, because the station is not designed for extended unmanned operations. Without a crew, there is no way to repair any further failures that may occur. There will be strong pressure to keep the ISS manned long beyond the point at which it becomes dangerous. (Some space medics think this point has already been reached.)

The second decision will be even more difficult, since it will be the final scrapping of a very expensive and highly touted project. I don't see that decision being made very quickly, given that all the International Partners will have to be consulted first. Somebody needs to give the order when there is still reliable communications, electric power, attitude control, and enough fuel for the retro burn. If the deorbit decision is delayed too long, it becomes impossible and we are stuck with a huge pile of space junk slowly spiraling down to an uncontrolled reentry that might scatter dangerous amounts of debris over a populated area. It will be very tempting to leave ISS tumbling in orbit and plan some grandiose rescue&repair mission, like the absurd robot repairman NASA has proposed for Hubble. There are even a few precedents they could cite (Skylab repair and a Salyut that was dead and reactivated). I think this approach is likely to fail because the ISS is just too huge and complicated to fix once it gets out of control. What are the policy implications of an ISS failure? Many people are saying that Shuttle RTF and Station completion are competency tests for NASA -- i.e. if they can't do those things then either Plan Bush will be killed or a new agency created to run it.

Shuttle and ISS are so fundamentally wrong in their basic concept and design that even the best engineers in the world couldn't save those programs -- and clearly the best engineers in the world no longer work for NASA. If RTF and ISS are really seen by the Administration as basic competency tests, then NASA is sure to flunk them.

On the other hand, the gradual collapse of the ISS disproves the notion that "ISS is teaching us how to operate in space." In fact, ISS is an example of how not to operate in space. The longer we stick with this pointless project, the more bad habits are learned by the various national space agencies involved with it. The sooner it is gone, the sooner we can learn the right way to explore space.

Jeffrey F. Bell is Adjunct Professor of Planetology at the University of Hawai'i at Manoa. All opinions expressed in this article are his own and not those of the University.

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Space Is Our Home, Not A Program
Los Angeles - Jul 08, 2004
When I walk with my head held high, I can see great distances and imagine great things. When I walk with eyes cast down, I see only my feet and the sidewalk below them. When it comes to America's vision for space, most of the commentary on President Bush's recently announced initiative is sadly sidewalk-bound.

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