Any Aerospace Engineer types around?

[Nobunaga]

... The shuttle has problems again. The Atlantis is in orbit now, and a small gash has been found in the heat tiles.

... A question from someone (me) who knows naught about this stuff: Why tiles? Can they not make one hard shell which covers the entire bottom of the shuttle?

... And, would this small (4-inch) gash be impossible to repair while floating in orbit? I mean, some kind of "zero-G glue gun" and a hammer?

... Certainly not a hot topic at present, but the last time we saw a gash in the tiles, the Columbia disintegrated on re-entry, killing everybody on board (2003).

...

[Jehan]

currently studying aerospace engineering, will get back to you in about 4 years.

[Nobunaga]

[2dimes]

I'm a casual shuttle observer.

A single hard shell covering the entire bottom, though I agree it would be better, might be impossible to make currently. It's quite a large area and the tiles need to be near perfect because of the temperatures they endure.

I don't know how many tiles that are produced fail the quality control stage but if it was a single piece, everytime it failed due to a single tile sized imperfect spot it would be a much bigger deal.

Also part of the benifit to making them as tiles, is they can be removed and replaced as single ones are damaged. Between missions tiles are checked and replaced. I believe they cannot be repaired.

It would be a much greater task to replace an entire bottom cover every mission.

One problem for them in orbit, is most of the tiles are a different shape from the rest, so packing spares would mean bringing along almost as many tiles as are on it.

If they are going to zip one up to them which one do they need to send and do you fire up a second shuttle to bring it?

[Jehan]

i thought nobunaga was suggesting replace the ablative tiles altogether with some material which can insulate and survive the reentry.

[2dimes]

A diaper used by Lisa Nowak?

[XenCobra]

currently studying aerospace engineering, will get back to you in about 4 years.

Give me about 8 years

[hecter]

Government conspiracy!

[Nobunaga]

... Yeah, one huge piece would have a rather hefty price tag if it had to be replaced every mission.

... But honestly (in my sheer ignorance) I can envision astronauts out there, space-walking with a big hi-tech caulking gun, filling the gaps with some manner of aspesto-polymer startrekium or some such.

... Maybe not.

... Just hope they get back alright. They've a week of work to do in space. I imagine that gap in the tiles is in the back of all of their minds. Were I on the crew I might volunteer to hang out on the space station (that's where they're going) and wait for the next ride home.

...

[2dimes]

I think the tiles have to be uniform throughout to absorb and disapate the heat through the entire unit.

The surface must be as smooth as possible to prevent one spot creating more friction. That would be the issue with the gap present.

Also it's probably kind of tough to manipulate a caulking gun with three pairs of gloves on.

[onbekende]

tiles are easely replaces, want to replace the whole shell each time there is a gash in them? because fixing small problems = replacing otherwise it isn't a smooth surface anymore

[Anarchist]

I'm a casual shuttle observer.

A single hard shell covering the entire bottom, though I agree it would be better, might be impossible to make currently. It's quite a large area and the tiles need to be near perfect because of the temperatures they endure.

I don't know how many tiles that are produced fail the quality control stage but if it was a single piece, everytime it failed due to a single tile sized imperfect spot it would be a much bigger deal.

Also part of the benifit to making them as tiles, is they can be removed and replaced as single ones are damaged. Between missions tiles are checked and replaced. I believe they cannot be repaired.

It would be a much greater task to replace an entire bottom cover every mission.

One problem for them in orbit, is most of the tiles are a different shape from the rest, so packing spares would mean bringing along almost as many tiles as are on it.

If they are going to zip one up to them which one do they need to send and do you fire up a second shuttle to bring it?

more detailed answer then I would have given