Sacramento - Apr 25, 2003
The central problem with the space station is that its builders keep changing the justification for its existence as they respond to the latest failures in the manned space program.
Despite the protestations of some, cost is a critical issue for the international space station program, with over 60 billion dollars still to be committed in new funding allocations from the US, Europe, Japan and Russia -- all of whom have growing budget deficits.
Meanwhile, the growing failure to actually do any significant amount of science on the station is bringing the critical debate of what the station is actually going to do for the next 10 years to a head.
Man-tended science operations are set to fall to 12 hours per week (only half of it for the U.S.) when the permanent crew falls to only two people during next week's expedition changeover. No one knows for how long the current crew and operational mode will last. And planning for a shuttle flight early next year will need to be handled very carefully -- any delays in launch, such as happen all too often, will leave any new plans in tatters once again.
Even after the full-time crew returns to three people, only about 29 hours per week of actual scientific work will be done (11 hours of it for the U.S.) -- at an incredible cost to the U.S. of over $10 million per man-hour of lab work!
The obvious problem here is access. And with the shuttle as the main transport cog in the whole station system, there are going to be continuing serious transport problems. Unless these and the other structural problems now consuming the space station program are resolved in some sort of acceptable manner, it is increasingly likely that the entire program will collapse sometime in the next 18 months.
Moreover, the longer the central problems remain ignored and unresolved then it becomes even more certain that the program will be mothballed sometime in 2004 or 2005 depending on the timeline that unfolds over the next 18 months.
Former NASA Historian Alex Roland among others has suggested the Station be reconfigured from a permanently manned platform into a "man-tended" platform, in which crews visit the Station periodically to return the material products of biological and zero-G manufacturing experiments to Earth and replace them with new experiments, but then quickly leave -- leaving the Station to spend most of its time unmanned, with is experiments operating automatically and under Earth remote control.
Whether this is practile with the ISS system remains to be fully known, but this scenario has been proposed many times for smaller orbiting labs, such as the Industrial Space Facility -- which NASA worked energetically to discourage Congress from considering last decade, on the grounds that it was a rival for the Station -- and the original form of the European Space Agency's "Columbus" laboratory module now scheduled for attachment to the Station, which was originally supposed to be a separate free-flying satellite.
The trouble is that it would do little or nothing to increase the Station's current ridiculously small science output, as only one of its actual laboratory modules - the American "Destiny" module - has made it to orbit yet.
At this stage science and engineering modules waiting to go up include:
All in all the International Space Station needs 17 more shuttle flights to reach its basic international partnership specifications.
Once the Station is completely assembled, crews, supplies, and experiments will indeed be carried up and down on other kinds of vehicles -- Russia's Soyuz crew vehicles and Progress cargo carriers, and the bigger European and Japanese "automated transfer vehicles" designed are expected to begin cargo flights to the Station by 2005.
For its purposes of getting to and fro from the Station the US has not prepared any alternative carrier vehicles -- relying up to now entirely on the Shuttle for that purpose -- but, if need be, it could swallow hard and massively increase payments to all its international partners to manufacture more of their own vehicles for this purpose, replacing most or all of the Shuttles' purely logistic flights carrying crews and supplies.
Only the Soyuz can survive reentry and return payloads to Earth, so some of those would have to be flown unmanned to return the experiments' material products to Earth as well as crews.
But unless those additional lab modules are carried up by all those additional Shuttle flights, the Station -- even if it keeps a permanent three-man crew -- will be so scientifically useless that it would make as much sense just to abandon it completely and replace it with separate unmanned recoverable research satellites anyway.
Is there any way to deal with this problem without continuing to risk human lives on a vehicle as dangerous as the Shuttle? There may be.
And that is to fly the Shuttle in an unmanned configuration from now on. O'Keefe himself suggested that this might be possible after the Orbital Space Plane is completed to serve as the full-time crew carrier for the Station, allowing the Shuttles to be reduced to pure cargo carriers. But there is no technical reason why this can't be done earlier -- indeed, why it can't be done immediately, with no Shuttle ever launched or landed in manned configuration again.
The Shuttle, of course, doesn't require its crew's guidance during launch -- and it already carries out its rendezvous to within a few hundred meters of the Station wholly automatically, with the crew stepping in only in cases of a malfunctions.
It has also been designed from the very start to be able to carry out its entire reentry and runway landing sequence entirely automatically, if need be -- from the first Shuttle flight, its computers have been loaded with every bit of the software necessary to carry out such automatic landings - except for actually flipping the switch to lower the landing gear.
NASA leaves that one entirely manual, presumably so as not to make the pilots feel unneeded).
The Soviet Union during the 1980s flew the one and only flight of its copycat shuttle - Buran, in a mission that ended with a perfect runway landing against a 57-km/hr crosswind.
It would be very easy to combine this with an emergency ability to tele-operation the Shuttle from the landing site if indications were received that the autopilot was bringing it in off target. The risk of a crash would not be similar to the current system.
One can visualize all future Shuttle missions to the Station being launched unmanned and rendezvousing and docking with the Station, after which the Station's own crew could enter the Shuttle in order to unload and attach all the Station modules and equipment it carried -- after which the Shuttle, once again unmanned, would detach itself from the Station and return for an automatic landing back on Earth.
Indeed, such unmanned Shuttles could also carry additional supplies for the completed Station afterwards, if NASA decided to do this instead of paying its partners to provide more vehicles for that purpose.
The Station's crews, however, would fly to and from the Station entirely on Soyuz capsules. Whatever one says about Russia's Soyuz, it DOES have an emergency launch escape system (which has already saved the lives of one crew), it is a capsule and therefore mostly self-stabilizing during reentry, and it has not killed any passengers since the Soyuz 1 and Soyuz 11 (Salyut 1) flights in the early 1970s.
Since then there have been several close calls the last being in 1997 when a retro rocket failed on Soyuz TM-25. Several engineers who have looked closely at the accident say the failure would mostly likely have caused serious injury to a passenger in the centre seat which on that flight was fortunately vacant.
But with it's launch escape system, and simplified reentry profile the Soyuz like all capsule spacecraft is now unquestionably a safer spaceship than the Shuttle and vastly cheaper per passenger launched.
Indeed, NASA could quickly expand the Station to a permanent crew of six people -- thus allowing half of them to spend all their time actually doing experiments, whereas a three-man crew must spend almost all of its time just keeping the Station's own systems running -- if it was willing to swallow its pride and pay Russia to keep not one but two Soyuz' permanently attached to the Station as emergency crew return vehicles.
In fact, the Aerospace Safety Advisory Panel officially recommended just this in its most recent report: "It may be that the only affordable option [for NASA] is the [permanent] addition of another Soyuz vehicle, and limiting the [station's] crew size to six [rather than the originally planned seven] for the foreseeable future."
If NASA does not do so, the Station -- no matter how many more lab modules are attached to it -- will absolutely have to remain in its current near-useless three-man configuration anyway until the OSP starts flying in nine years.
During this period, the only times it will be even moderately scientifically productive will be during its periodic brief visits by Shuttle crews -- who could just as easily carry out all the science experiments on labs carried in the cargo bays of separate Shuttle flights anyway.
But if NASA accepts the addition of a second attached Soyuz, the only other thing needed to immediately raise the Station to a permanent crew of six would be the attachment of one additional "Habitation Module" built by the US.
The one big catch in changing immediately to unmanned Shuttles for future Station visits is the problem of docking. The Russians have been carrying out totally automatic dockings routinely for 35 years, and Japan has now also done so -- but the US has virtually no experience with auto docking.
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.|