quoted from

http://spaceflightnow.com/shuttle/sts107/030208object/

I thought that any impact severe enough to damage the orbiter would be felt/heard by the crew and that they made no such report. The article also mentions several other causes all of which are benign.

[edit typo]

<font size=-1>[ This Message was edited by: Sleepy on 2003-02-09 08:53 ]</font>

On the network news last night (I forget which network -- I saw a Columbia segment on all three) it was reported that a debris impact on some area other than the crew compartment could go unnoticed and still cause enough damage to be serious, especially if it occurred in a critical area (such as a wing leading edge).

As we've discussed before, a lot of the orbiter can't be visually inspected, and there isn't enough structural sensor coverage to detect the sort of minor damage that might lead to a cascade of failures during reentry.

So, of the three possibilities we have so far - damage from the insulation during lift-off, lightning or sprite or elf or <the blue one>, or space debris - which would be the most unsettling or cause NASA the most difficulty to resolve for the shuttles to be allowed to launch again?

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"As I lay beneath the Southern Cross, the stars tell more than I could" . . . David Meece

For what its worth - my first guess in order from easiest to hardest:

1. Tile damage during lift-off from debris from the ET or SRB’s.
2. Damage from orbiting debris.
3. Lighting, sprite, elf.

My reasoning is that if debris impact from the ET or SRB is the problem the fix is within NASA’s expertise to find the solution. Damage from orbital debris, if caught, gives NASA time to react with repairs, alternate reentry profiles (not likely – see other threads) or rescue.

A lighting/elf/sprite hit during initial re-entry like we’re guessing might have happened to STS -107 that causes structural or electrical damage leaves no options – just no way to react to it.

However, on second thought, there might be ways to protect the orbiter from lighting/elf/sprites, to prevent structural damage but I don’t know. If so 2&3 might reverse but either way these two are the hard ones.

A thin, light, electrically conductie grid wick some beefy spikes (lightning rods) at the corners should do the trick. Remember reading somewhere that lightning rods prevent strikes by bleeding the exess voltage away from the protected structure, but that was an older book....

edit: the usual (spelling)
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<font size=-1>[ This Message was edited by: darkhunter on 2003-02-09 16:44 ]</font>

But the shuttle should be protected anyways. Isn't the skin of the shuttle aluminum? Would this not dissapate the energy along the skin and protect the interior?

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GIYUL :-)
"It takes Thousands to fight a battle for a mile, Millions to hold an election for a nation, but it only takes One to change the world." - Dan Sandler 2002

I don't think the tiles themselves are conductive--the air (space?)frame would survive just fine in a lighning stike, but to get to the frame it goes through the tiles.

Wouldn't take a lot on the outside: in a thunderstorm you're safe in a car NOT because of the rubber tires insulating it, but because the electricity is conducted around the outside of the metal body when it's struck. (Saw it on Discoery Channel once--it was pretty cool). And a cars bodywork (especially the newer ones) isn't all that thick...

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"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels it finds the darkness has always got there first, and is waiting for it." — Terry Pratchett, Reaper Man

441!!!! :)

That is one problem that automakers are saying with the new plastic bodies of cars and planes. Plastic is not conductive and you are just as worse off as you were outside the car.

Also a pain to repair dents in [img]/phpBB/images/smiles/icon_smile.gif[/img]

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"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels it finds the darkness has always got there first, and is waiting for it." — Terry Pratchett, Reaper Man

441!!!! :)