I know that the bottom of the pace shuttle is covered with silica-based tiles, which serve to insulate the aluminum body of the shuttle, from the heat (>3000 F) of re-entry into the atmosphere. As I understand it, these tiles are checked very carefully, and missing ones are replaced immediately. My question: suppose just one tile were to fall off-would the heat influx from that smalla area be enough to cause the destruction of the spacecraft?
And, are the tiles usually checked by the crew when they reach orbit?
Seems like a hairey prposition, to attemp re-entry with a missing tile…does the shuttle caryy repair kits for the tiles?
Not according to the news reports I was listening to yesterday. It’s my understanding that some loss of tile is expected on each flight.
The astronauts, in general, do not have access to the bottom of the orbiter. They don’t train for such an EVA. This means that, ordinarily, they cannot make a visual inspection. They do not carry extra tiles. They do not have any tools to repair or replace tiles.
There is usually some damage to the tiles during takeoff, and this is just considered normal wear and tear, and does not jeopardize the orbiter.
A few lost tiles aren’t cause for concern, especially if they’re not contiguous (touching). However, if several tiles came off in a patch, this could be a problem. This would result in a small pocket where air could collect and start tearing off even more tiles in a sort of zipper effect, leading basically to what we saw the morning of Feb. 1st. There are a few ways they could inspect for damage, but none easily. If they were docking with the ISS, they could approach “belly-up” and have the Expedition crew inspect the underside. Back when the MMU was in use, they could have inspected it on an EVA, but that’s impossible nowadays. I believe on one of the earlier flights they actually used a spy satellite to inspect the belly of the shuttle.
Shuttles lose tiles all the time. It’s no big deal. More than likely, the foam that broke away from the fuel tank impacted the wing with more force than was thought, and may have weakened the wing, or parts of it, structurally - a crack maybe.
On the other hand, this was our oldest shuttle and had already flown several missions. It’s possible there was already some structural fatigue present and the errant foam did nothing at all.
I’m banking on the foam though. Foam rubber can be pretty dense, and the “piece” that broke off could have weighed several hundred pounds. Being the foam was falling down and the shuttle was going up, the impact, even if glancing, was at a high rate of speed, increasing the chance of damage.