CNN
Posted on 02/01/2003 10:18:41 AM PST by Timesink
Seven astronauts, including the first Israeli in space, were lost Saturday when the space shuttle Columbia broke apart in the skies of Texas. The incident occurred at an altitude of some 200,000 feet, shortly after reentry and 15 minutes before Columbia had been scheduled to land at Cape Canaveral. TIME science correspondent Jeffrey Kluger explains some of the possible causes and consequences of the accident:
|
|
CNN
|
|
TIME.com: What are the possible scenarios that could have caused this disastrous accident on the shuttle's reentry into the Earth's atmosphere?
Jeffrey Kluger: There are three possible scenarios that explain this event. The first, which I believe is the likeliest explanation, would be an aerodynamic structural breakup of the shuttle caused by it rolling at the wrong angle. Remember, after reentry, the shuttle is descending without power, which means astronauts at the controls can't compensate for a loss of attitude by using the engines, they can only do so using the flaps. And that's extremely hard. Astronauts describe piloting the shuttle on reentry as like trying to fly a brick with wings. It's very difficult to operate, and even more so to correct any problems.
A second explanation might be a loss of tiles leading to a burn-through. (The shuttle is covered with heat-resistant tiles to protect the craft and those inside it from burning up in the scorching temperatures caused by the friction of reentry.) But I think that explanation is unlikely, because the tile-loss would have had to have been quite substantial for that to become possible. You'll hear a lot in the next few days about things falling off the shuttle during liftoff. But it often happens that they lose a few tiles, and I'd be surprised if it happened on a scale that could make an accident of this type possible.
The last option is some kind of engine failure leading to fuel ignition. Although the main tanks are mostly empty, there should still be fuel left in the maneuvering tanks. But probably not enough for an explosion that could have caused this breakup.
And just in case anybody was wondering, you can almost certainly rule out terrorism as a cause. This incident occurred well above the range of shoulder-fired missiles. And it would probably be easier to sneak a bomb onto Air Force One than to get one onto the shuttle.
TIME.com: So is reentry the Achilles heel of the shuttle program?
JK: No, the Achilles heel has always been liftoff, and the dangers posed by massive fuel load involved. Reentry has, of course, always been a difficult part of the space program. But this is, in fact, our first fatal accident on reentry. Apollo 13 is remembered as our most difficult ever reentry, but the ship and crew survived. The Soviets lost a crew on reentry in 1970 after an oxygen leak that caused the cosmonauts to suffocate on the way down. Reentry is a very difficult process, but the Russians mastered it in 1961 and we did the same a few years later.
TIME.com: Are shuttle crews trained to respond to the scenarios you've described?
JK: Yes, they're trained to deal with loss of attitude on reentry, and a range of other emergencies. But astronauts are not trained to deal with situations that result in certain death, because that would be a bit like training for what you might do if your car went over a cliff — in some situations there simply isn't anything you can do. One irony, though, is that NASA hadn't trained astronauts to deal with the sort of quadruple failure that occurred in Apollo 13, because they assumed that such a scenario would result in certain death. But the astronauts survived.
TIME.com: What are the immediate implications for the space program of Saturday's disaster?
JK: Following the precedent of the Challenger disaster in 1996, it's unlikely that NASA will undertake any further shuttle missions or any other manned space flights for the next two years. One immediate problem, though, is the International Space Station, which currently has a crew of three on board. They might consider one further flight to bring that crew home — the other option would be for them to return aboard a Russian Soyuz craft, which isn't the most comfortable or the safest ride. Beyond that, however, the space station is likely to be left unoccupied for a long time. NASA won't want to use the shuttle again until it can establish the cause of today's accident, and fix it. Now that we've lost two shuttles out of a fleet of five, it's even conceivable that the shuttle won't fly again. The shuttle was built as a space truck, and then the International Space Station was built to give it something to do. Both programs are likely to suffer as a result of this disaster.
Also, it has air entrained in it, and as the Shuttle ascends and the air expands, chunks of TPS have been known to separate.
The fix for that was to drill "air holes" into the foam to let the trapped air out without taking the foam with it.
Disclaimer: I haven't worked at KSC for almost 4 years, so their materials and procedures may have changed.
Is that a typo?
It has been years since they used tape recorders. Everything is digital nowadays. I agree that it is somewhat unlikely that they survived impact but I don't believe it is impossible. Their value would be in recording the last voice communications amongst the crew -- clues to the mishap might reside in those comments and possibly some thoughts that might provide the families with last thoughts. I know there was controversy on another thread about the existence of such recorded conversations from Challenger but I am here to say that they exist and were never made public by official fiat.
I really don't know on this one. I sure hope so.
STS-107 (113)
Crew:
Milestones:
Payload:
Mission Objectives:
Click here for Additional Info on STS-107 Research Mission, Freestar (MEIDEX,SOLSE-2,CVX-2,SOLCON-3, LPT,SEM,PSRD)
Launch:
Orbit:
Hardware:Landing:
Mission Highlights:
 KSC Home  Mission Index  Last Mission STS-113  Next Mission STS-114
Last Updated Saturday February 1 11:49:43 EDT 2003Jim Dumoulin (dumoulin@titan.ksc.nasa.gov) |
I am not sure the tooling still exists.
I had friends working on the next generation until it got canceled.
Final radio transmission between Columbia and Mission Control:At this point, my money's on a burn-through.Mission Control: 'Columbia, Houston we see your tire pressure messages and we did not copy your last.'
Columbia: 'Roger, uh, ...' (transmission breaks off after the crew member starts to stay a word beginning with the sound 'buh.')
It can also go directly to the ground, but that wouldn't work since they were in the "re-entry ionization blackout" at the time, and they have to be over a ground station anyway.
The engineering data (strain gages and thermcouples, etc.) are recorded on the OEX recorder for retrieval only after landing. That data is not downlinked.
But didn't the catastrophic failure happen right during the time when communications is blacked out during re-entry?
Possibly, time will tell. Don't forget that an improper angle of attack on atmospheric reentry could cause environmental conditions to exceed the design limits on the Thermal Protection System. I can't imagine the circumstances that would cause the software to issue improper instructions to the Reaction Control System. That software may be the most tested stack on the face of the planet. Brookhaven did a truly remarkable job with it. It almost certainly has to be a hardware failure of some flavor.
I'm guessing some duff tiles. But not much to go on at this point.
It does. Don't forget that we replaced the Challenger, with the Enterprise I think. It would take a couple of billion dollars. This is a real, honest to God nexus in manned space operations. I look forward to seeing it resolved.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.