Columbia accident data deciphered

[AggieDave 6]

I wonder if Nasa will come up with some sort of "wrecker service" for their shuttles now? Not that you could tow one home, but you could have a seperate platform to make emergancy repairs or do an emergancy evacuation to the "tow-truck".

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[kallend 2,147]

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Don't suppose you know what it consisted of?

I'm curious how you have a workable goop at a temperature close to absolute zero.

Exothermic reaction of the goop components?


David

What do you mean by the temperature of space? The Shuttle cools and warms as it moves in and out of Earth's shadow. Space is like a big vacuum flask.

...

The only sure way to survive a canopy collision is not to have one.

[nacmacfeegle 0]

"I'm curious how you have a workable goop at a temperature close to absolute zero. "


I'm thinking more of an intumescent paste, which would cure (local heat pads similar to welding heat treatment units) and seal as it was heated, kinda similar to Pitchar, or Chartek, but a whole lot thicker than about 12mm.....

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He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. Thomas Jefferson

[kallend 2,147]

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>Are you sure? I was under the impression that SpaceHab had a door . .

It had a door, but you'd have to depressurize the shuttle to use it, and that would require everyone to use their altitude protection suits which are designed for dire emergencies only - they are not tested to the same levels at the EVA suits. That would expose everyone to a tremendous amount of risk.

If you just wanted to evacuate the orbiter to, say, the ISS, you could just jettison the main door, but then of course you couldn't re-enter the atmosphere, ever. (assuming the orbiter had enough delta vee to reach the ISS which it didn't.)

Columbia was the heaviest Shuttle, and could not reach ISS with a useful load. Therefore it had not been equipped to dock with ISS.

That is not to say that the ISS itself couldn't be equipped with a "lifeboat" for just such contingencies as this.

...

The only sure way to survive a canopy collision is not to have one.

[kiltboy 0]

I was thinking that the goop would have a freezing point therefore trying to apply and work it would prove difficult in the cold. Also the change in pressure would mess with the boiling point of the goop.

I wasn't thinking of sticking it in the sun's rays to warm it up to a workable temperature.

I was also curious what the heating cooling cycle would have on the curing of the paste/goop to form the bond.

I'm not an adhesive chemist so I was digging for some info on the chemistry part of it.

David

[billvon 3,111]

>I think the fact that Nasa sent a crew up with NO WAY to inspect their
> craft and NO WAY to repair tiles was a VERY FOOLISH thing to do..
> What a bunch of fucking brain wizards.. That was just plain dump..
> Where is their sign??

OK, Rhino, how do they protect against a meteoride? Where's their laser to vaporize the object? How do they inspect the insides of the wings for damage? What do they do if they lose hydrazine on-orbit and can't run the APU's? Don't they have a five gallon can of hydrazine they could use? What if they break a window; how does any of the crew survive? Surely if you could come up with a plan to fix the tiles, they could come up with plan for a simple broken window!

I know some of the people that worked on the shuttle program, and they are wizards. They have come up with abort scenarios that you haven't even considered. Some are quite possible (and have been used) like abort-to-orbit. Some are on the hairy edge of possibility, like return-to-landing-site. Some are not really practical, like a way to protect the crew against a broken window - and in this case tile repair as well.

Space travel is a dangerous endeavor. It is barely possible with our best technology. We have lost people before; we'll lose people again. All of them go willingly. Some of them will die. We can try to keep them safe, but the only way to keep them completely safe is keep them on the ground.

The end result of all this is that they will add some way to repair tiles on-orbit, even if it's not that effective. Which means the next accident will happen due to a hydraulic system failure, or an RCS isolation valve leak, or a premature parachute deployment. You can reduce the odds, but you just can't eliminate them.

And please keep the attacks to a minimum. I'm sure if a bunch of marines died due to a helicopter crash in fog and someone called the pilot "a dumb fuckin brain wizard" you'd be upset; please consider that other people are dealing with the same sort of feelings.

[kiltboy 0]

I'm trying to picture this.

So the paste is on the back of the tile and you hold the tile in place. Then the sun heats up the shuttle and the paste melts and cures onto the metal?

David

[billvon 3,111]

>That is not to say that the ISS itself couldn't be equipped with
>a "lifeboat" for just such contingencies as this.

There was a plan for an ISS lifeboat called the X-34, which was recently cancelled. It still couldn't have reached the orbiter; the inclination of its orbit was too far off for any planned vehicle other than a dedicated manned OTV. That was cancelled too of course.

[rhino 0]

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I'm sure if a bunch of marines died due to a helicopter crash in fog and someone called the pilot "a dumb fuckin brain wizard" you'd be upset;

This wasn't pilot error. This was piss poor planning..

Broken windows? I believe when in orbit the bottom of the craft is facing away from earth to absorb that sort of thing. Or at least try..

[billvon 3,111]

>This wasn't pilot error. This was piss poor planning..

Most pilot error is piss poor planning.

>Broken windows? I believe when in orbit the bottom of the craft is
>facing away from earth to absorb that sort of thing. Or at least try..

Yes, they try. Still they've found pits in the windows that extend almost all the way through before; meteorides don't always come from where you expect them to come from. A particle the size of a housefly could take out a window with no warning and no chance to get into altitude protection suits.

[PhreeZone 20]

The bottom of the orbiter faces the earth for some orbits to allow the orbiter to be heated. Thats one reason why going under the orbiter is dangerous, its in complete shadow.

>This wasn't pilot error. This was piss poor planning..

It could be argued that they should have never tryed to fly a chopper in the fog and thats piss poor planning then too.

I'd advise you to check out the procedue book from Nasa on in flight emergencys. Last I heard it was about 5000 pages and about 4 inches thick and covered everything from what to do if a switch cover pops off to ways to repair the toliet to metorite strikes to leaking gases to liquids floating in the cabin. Some like cracking in the glass or loss of certian fuels are deemed unrecoverable and are deemed likely to cause LOCV. In those cases there is nothing that can be done except hope that LOCV does not occur. Granted the astronauts will don their survial suits and have Nasa punch in a new reentry that will try to minimize stress on the affected area, but in the case of fuel loss there is nothing that can be done. No ammount of planning can fix issues like that.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Gawain 0]

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Performing an unplanned EVA is a very scary thing. And the heat tiles are so delicate that an astronaut could actually do more damage than good while fumbling around out there. It would require a robotic arm to hold the astronaut in place to do the job and as Bill stated before, it was not installed for this flight.

I am not an expert, but upon reading the emails that were exchanged at NASA, pros and cons of an EVA were discussed and there was an advocate that said "Seems to me the benefits of an EVA has more pros than cons. Can't imagine that an astronaut (even on a crappy tether arrangement) would cause MORE damage than what he is going out to look for."

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

[billvon 3,111]

>Can't imagine that an astronaut (even on a crappy tether
> arrangement) would cause MORE damage than what he is going out
> to look for."

Well, right. But losing an astronaut due to a crappy tether arrangement, even if it doesn't damage the orbiter in the meantime, isn't the best outcome.

[PhreeZone 20]

The tiles are fairly delicate, you know that crunchy foam that comes in blocks that with some pressure can be squeezed to about 1/8 its thickness? Thats about how delicate the tiles all except instead of compressing they will crack and can lead to more tiles breaking off. My second cousin used to work for Nasa as an engineer and he expressed to me a few times that he was always impressed that something that could withstand the heat and pressure of reentry could be so delicate that banging it into something could lead to cracking it. The replaced tiles on every flight take weeks to propery mount and attach. The goo that was proposed in the early flights was like a paste that you just caked on layer after layer untill you thought it would last. (Real exact science huh? )

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[diverdriver 7]

What memo was that? I haven't seen that one. And was it generated for this mission or just in general about shuttle missions? The tile coverings are extemely delicate. An astronaut on a limp tether would have to stabilize himself by touching the tiles. This could produce more damage than is already present. Not really an option. Doesn't mean they won't one day come up with a viable plan to do it. Just right now with our current limitations on weight and vehicle type we have to work with what we have. Carrying extra tiles does not seem to be a realistic option. If the damage is so bad that a repair is necessary then it may be too bad to be fixed. Every shuttle mission has had tiles fall off. It is an accepted part of these missions. No doubt NASA studies what tiles are missing and how it can be prevented from happening. I doubt this has been a back burner topic.

Chris

[kallend 2,147]

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>That is not to say that the ISS itself couldn't be equipped with
>a "lifeboat" for just such contingencies as this.

There was a plan for an ISS lifeboat called the X-34, which was recently cancelled. It still couldn't have reached the orbiter; the inclination of its orbit was too far off for any planned vehicle other than a dedicated manned OTV. That was cancelled too of course.

Are you sure? The Columbia still had enough fuel on board for the de-orbit burn. Had this been used for changing the orbit instead, it's possible that the "lifeboat" could have reached it.

Quite likely the cheapest option for problems like this is to keep a couple of Vostoks on hand at KSC, ready to be launched at, say, a week's notice, to evacuate a crew. Vostoks are quite inexpensive and have simple systems (everything being relative). There are enough high-res optics around on Earth and on satellites to be able to perform a thorough inspection of an orbiter once it reaches orbit.

...

The only sure way to survive a canopy collision is not to have one.

[billvon 3,111]

>The Columbia still had enough fuel on board for the de-orbit burn.

The orbiter only needs about 220 f/s delta-vee to deorbit. It takes about 200 f/s delta-vee to change orbital inclination by even one degree. Since the OMS system (without the OMS fuel kit) carries about 1000 f/s worth of fuel, that's a max inclination change of 5 degrees. The ISS orbits at an inclination of 51 degrees; Columbia was at an inclination of 39 degrees.

>Had this been used for changing the orbit instead, it's possible that
>the "lifeboat" could have reached it.

Again, unlikely. Orbits aren't that easy to chance outside of very specific parameters (i.e. you can change your position relative to another object in the same orbit pretty easily.)

But let's say that the orbiter could use all its fuel to change its orbit; now it's at 44 degrees, permanently marooned in orbit. An X-38 crew return vehicle launches from the ISS, uses all its fuel and just makes it to 44 degrees. They rendezvous. Now you have to have all seven people spacewalk without EVA suits, only pressure suits, without tethers or propulsion, and move onto a different spacecraft that's small enough that it will move when they land on it. This has never even been tried before. Then they have to get inside and close the door. Then what? They've used up all their fuel; they can't deorbit.

But let's say they have an extra thruster package or something to deorbit with; now we're really reaching. They have to do all this, from launch from the ISS to landing, within nine hours; that's all the battery power the X-38 has.

Sounds pretty sporty to me.

[nacmacfeegle 0]

Oaky, lets get this clear, I'm just discussing this from an outsiders viewpoint. I work mainly on the design of large offshore petrochemical plants....So we have an entirely different set of challenges. However, in the interests of debate
"I'm not an adhesive chemist so I was digging for some info on the chemistry part of it. "
We are using a lot of composite repairs to structures and pressure retaining systems offshore in the North Sea.
We have inflatible 'habitats' in which we can control the curing and environmental conditions. Which, if we need any sort of performance guarantee, have to be fairly well controlled. I'm thinking something similar would be required and may be feasible.

"So the paste is on the back of the tile and you hold the tile in place. Then the sun heats up the shuttle and the paste melts and cures onto the metal? "

Once you have control of the environment, the heat from the sun becomes useful but not critical. Here's the rub though. I'm assuming most of the tiles are of fairly unique form and geometry, so carrying a spare set of tiles would be like carrying a spare wing, as mentioned earlier. Also there is no guarantee that a tile would break off cleanly in one nice chunk. So you would need some means of trowel applying a cement type repair, that would provide similar protection as the original tile. You would also have to guarantee its adhesion, so may need to do some surface preparation, shot blasting or needle gunning?
Maybe chemical cleaning. I'm figuring none of this has been tried in space before either.

It seems to me that the idea of a space lifeboat/tow truck, based at the ISS, is more likely to be technically within our grasp for the time being. That said, I don't think we are too far away.

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He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. Thomas Jefferson