Aerodynamics May Explain Space Shuttle Breakup: possible causes, consequences of Columbia disaster

TIME.com ^ | February 1, 2003 | Jeffrey Kluger

[Timesink]

Saturday, Feb. 01, 2003

'Aerodynamics May Explain Space Shuttle Breakup'

TIME science correspondent Jeffrey Kluger examines the possible causes and consequences of the Columbia disaster

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.

[Fred Hayek]

The Mercury-Redstone suborbital flights of Grissom and Sheppard used a different type of heat shield, in that case a heat sink. Heat sinks were also used on the RV's for the Atlas D and Thor missiles. The Mercury-Atlas capsules used an ablative heat shield. These were first tested in unmanned orbital flights.
Before the Vostok 1 (Gagarin's ride, I won't call it a mission since it was all ground control), the Soviets tested the Vostok craft with 5 Sputnik launches.

[Movemout]

"If not, you are as technically illiterate as the rest of the media loons including Dan Blather. "

I'm sorry, I can't focus on your point. I am much more interested by the brown material oozing out of your ears. The telemetry between shuttle and ground is uninterrupted from deorbit to landing. Do just a little bit of research and you will find this to be true. P;ease do not compare me to Dan "What is the frequency Kenneth?" Rather. There is a brief period when voice commo is nonexistant by your proposition but telemetry continues unabated.

[TigersEye]

bump for the link at #113

[Movemout]

I'm signing off. Eight hours of trying to help is enough for me. I truly regret the loss of our astronauts and the effect on their families and us. There will be endless investigations and finger pointing. I also regret that. I hope that we, as a nation, have the intestinal fortitude to continue to explore. If not, our great grandchildren may be speaking Chinese.

[Axenolith]

Seeing your experience I'm taking that as a healthy compliment, thanks.

I'm hoping we don't have a 2+ year wait here to get back in the game. Its bad enough that the program is basically on a shoe string. I want some of our eggs out of this basket and believe space exploration is THE way to go in the long run economically, from the military strategic standpoint, and because it provides a beacon of hope and dreams to even the lowest of us.

If I had a Gates-esque fortune I'd offer all of it for a chance to go up, even if it was in the worst tin can piece of Russian scrap available. People say to me "but its dangerous" and I reply that they've got to be high not to be willing to take even a 5 or 10% chance of death to do something that until 40 some odd years ago NO man had ever done. Even now only the most elite, the best, brightest and most blessed of humanity has ever done it. Have, from probably their childhood, set their sights on the heavens, surpassed thousands of others in their achievements, and won the rare and precious privledge of looking down from the heavens on this small blue orb or travelled to its moon.

Its hard to hold back a tear for the families and loved ones of the seven who perished but in my heart I know that that seven along with the Challenger crew, the Apollo crew and the Russian cosmonauts that have perished in this endevour will allways stand at the head of the line of greatest representatives of the human race who ever said "Follow me! Lets discover whats beyond there!"

Thanks to you and others like you also for devoting the years to making it possible too!

[FReepaholic]

>>...Seems to me that if it was a spacecraft attitude problem, the words would have been different...<<

I tend to agree with you. If the orbiter had been in an unusual attitude due to drag caused by tile loss, they'd know about it and be reacting to it.

[Erasmus]

Well in all seriousness I think you're making the best of a tough situation. Sometimes, like today, we all have to.

By the way, just yesterday a friend suggested I donate my brain to Science. She checked on it and reported to me that Science has an opening next Wednesday afternoon.

[Jael]

A review of the records of the STS-86 records revealed that a change to
the type of foam was used on the external tank. This event is significant
because the pattern of damage on this flight was similar to STS-87 but to a
much lesser degree. The reason for the change in the type of foam is due to
the desire of NASA to use "environmentally friendly" materials in the space
program. Freon was used in the production of the previous foam. This method
was eliminated in favor of foam that did not require freon for its
production. MSFC is investigating the consideration that some
characteristics of the new foam may not be known for the ascent
environment."


http://www.freerepublic.com/focus/news/834139/posts?page=54#54

[ajihle]

The foam on the ET is really there to prevent or at least reduce the amount of ice that forms due to condensation. Pieces of ice breaking off can cause serious damage to the Orbiter itself. Same goes with other rockets used in the past. Remember the old Apollo launches with all the ice breaking of on liftoff?
The piece of foam that broke off on STS-107 wasn't very large. But was it just foam, or foam with ice formed on it? The ice would make the impact much more significant. Although NASA did say, with the initial report, that it was unlikely that it posed a danger. As we see, that could possibly be wrong.
I fear that we will never, never find out what happened to Columbia. Unlike Challenger there we really no hi quality, hi speed cameras aimed at the craft at the timeof breakup. Also, Columbia broke up at just over 200,000 ft. at Mach 18 or so. Challenger Exploded at 65,000ft at Mach 1.5 (going on memory here.) The Atlantic Ocean impeded parts recovery, but the open terrain of Texas will certainly make recovery easier. But my God the debris field is enormous. It makes the Challenger debris field look small. 25,000 square miles or so? How much will we recover? Maybe 25%? That may be on the high side.
As for the "Black Boxes" yes there were FDR (Flight Data Recorders) on board. But they were NOT hardened as "Black Boxes" on aircraft are. As for the FDR being analog or digital, well I don't know. Hopefully, since she went thru a refitting just a few years ago to the "Glass Cockpit" upgrade, they will be digital and not tape.
Now something that really annoys me is all these so-called experts on TV that speak about the Shuttle. It reminds me of the CNN reporters during the Gulf War who simply didn’t know a soviet T-72 from an American M-1A1. I tired of hearing the "experts" talk about friction being the heat source during reentry. Anyone out there with an aerodynamics degree? The heat is caused from compression. There is some heat from friction, but it's minor compared to compression. As the shuttle (or any other super or hypersonic aircraft) moves thru the atmosphere, it pushes the air out of the way, thereby compressing it. When you compress something the energy is converted to heat. Huge amounts of heat. That it why the temperatures on the surface of the shuttle reach 3,000 degrees F.


In my humble opinion,

AJIHLE
P.S. Sorry about any typos, I was in a hurry.