airship...
<<Regarding the sensors, I understood from the NASA press conference that there were 12 or more temperature sensors in the left wing area, all of which operated normally until moments before the accident>>
This is an area that is interesting. NASA have commented in detail on how numerous temp (and other) in the left wing were progressively lost, and small mention of how some showed temp rises - this from Sky's site:
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1356: Temperatures in the housing of the left main landing gear rise. At this point the shuttle is 207,135ft or 39 miles up and travelling at 12,500mph - 18 times the speed of sound.
1358: Temperature sensors in the left wing, embedded in the structure of the vehicle, stop working.
1359: Pressure and temperature sensors for both tyres on the left main landing gear go offline
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What I'd really like to know is what the << Temperature sensors in the left wing, embedded in the structure of the vehicle>> showed prior to stopping working. Presumably these sensors are there to monitor the renetry, if only "after" the event.
<<Needless to say, it was probably by far too late to abort re-entry by the time these anomalies occurred?>>
They start 1 (of 3) APUs (1 needed to power flight controls and landing gear) in orbit prior to "deorbit" (a long burn to slow the shuttle down). Once deorbit starts, its coming to earth whatever! It has no fuel to regain all that energy - in fact, what little fuel it has remaining is "dumped" after the deorbit burn. But again, even if any anomolies had been seen, what to do? All one can really do is recover to earth and "hope for the best".
<<there had been significant damage to the heat-shield after launch, would these same sensors have not registered anomalies during the shuttle's orbits, when the underside would have been (repeatedly) exposed to wide fluctuations in temperature from exposure to the sun?>>
Interesting - but doubt it. The Heat Shield / Tiles protect against a short / sharp rise during renetry. In orbit things take longer, so probably expect to see fluctuations?
<<just as the lunar module on one of the Apollo missions provided relief (or was that just a film?!), >>
The Apollo missions had an escape rocket attached to the manned capsule. From Prior Launch to not too long after (it was then jettisoned) it could be used to drag the capsule away, and let them come down be parachute. Not suitable for the shuttle because its (only) way of landing is using the whole thing as a glider. They put some pole in with parachutes after Challenger, but I think the circumstances it can be used are very limited!
<<an EVA airlock and docking system are both valid and pre-requisite for would-be rescues of near-Earth missions. >>
It has a dead standard airlock into the cargo bay. However, any EVA system needs something to EVA into. What?
<<3. "and sending an SOS would have been an entire waste of effort" - frankly yes. - in this case there was no "Houston, we have a problem" message because Houston didn't think it had a problem. In space, nobody cries "Wolf"!>>
Some Prof on Sky making possible suggestion Mission Contorl knew all along recovery would be / may be fatal:
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Pressed by Jeremy Thompson, Prof Balogh said he was satisfied that NASA had been fully aware of the problem and had, in all probability, known all along it was potentially fatal
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I note from the NASA brief yesterday they only became aware of the bit falling off the day after launch - so no possibility of any decisions to be taken during the launch phase.
NoD