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I have to second this. I worked on two NASA space telescopes (both X-ray telescopes), and although we had on the ground something like the telescopes that were

I have to second this. I worked on two NASA space telescopes (both X-ray telescopes), and although we had on the ground something like the telescopes that were flown, the equipment on the ground was not flyable, and if the launch rocket had blown up, we would have been SOL. In fact, some of the folks down the hall from me had a telescope they were working on fail to deploy properly after launch due to the canister containing the telescope not opening. There was no spare telescope--they had to start over from scratch.

samstave 14y ago
So there is an unopened space telescope sitting in a canister in orbit? Wouldn't a device to open. The canister be cheaper than starting from scratch?
- excuse-me 14y ago
  No, generally when a launch fails the satelite doesn't reach it's final orbit. Either part of the shroud (rocket nose fairing)( fails to release and the extra drag makes it reenter - or even if it is in a stable orbit the lack of power causes it to freeze. A manned Shuttle service mission cost something like $500M / $1Bn (depending on how you do the accounting) so it was never really practical to retrieve a damaged satelite from a purely economic perspective.
- nessus42 14y ago
  As I understand it, the designated time arrived and the canister was supposed to be open, but wasn't. A latch had failed. One or more of the payloads inside the canister started deploying themselves anyway, wrecking themselves and everything else inside the canister. The telescope in question wasn't worth terribly much, at least compared to a Shuttle launch, which at the time cost at least $500 million, not including the cost of any payload, so even if the telescope hadn't been ruined, trying to rescue it wouldn't have made any sense. There were some other satellites in the canister, however, and IIRC, the total value of all the satellites was nothing to sneeze at.
excuse-me 14y ago
Some colleagues of mine had an even worse day. The launch went perfectly but the lens cap released while the Earth was in the IR camera field of view and the entire mission coolant was burned off in a few minutes.
- gammarator 14y ago
  (WIRE: http://en.wikipedia.org/wiki/Wide_Field_Infrared_Explorer http://en.wikipedia.org/wiki/Wide_Field_Infrared_Explorer)
gammarator 14y ago
(HETE: http://en.wikipedia.org/wiki/High_Energy_Transient_Explorer http://en.wikipedia.org/wiki/High_Energy_Transient_Explorer)
- nessus42 14y ago
  Yes, that was the one! The two telescopes that I worked on that had no such problems were XTE (aka RXTE) and AXAF (aka Chandra). I only did a little bit of work for AXAF, but I worked on XTE for years. In addition to some other miscellaneous software, I wrote the code that let the scientists configure the parameters of the on-board data processing computers. There were some serious issues with AXAF, though. The CCDs were damaged by some sort of unexpected particle radiation. Prior to this damage, the CCDs on AXAF were the most carefully calibrated CCDs ever manufactured. Or so I was led to believe. And the damage, although not fatal to the mission, did ruin the calibration. This was pretty discouraging to a colleague down the hall, since he had spent years making it so perfect.

samstave 14y ago

So there is an unopened space telescope sitting in a canister in orbit? Wouldn't a device to open. The canister be cheaper than starting from scratch?

excuse-me 14y ago
No, generally when a launch fails the satelite doesn't reach it's final orbit. Either part of the shroud (rocket nose fairing)( fails to release and the extra drag makes it reenter - or even if it is in a stable orbit the lack of power causes it to freeze. A manned Shuttle service mission cost something like $500M / $1Bn (depending on how you do the accounting) so it was never really practical to retrieve a damaged satelite from a purely economic perspective.
nessus42 14y ago
As I understand it, the designated time arrived and the canister was supposed to be open, but wasn't. A latch had failed. One or more of the payloads inside the canister started deploying themselves anyway, wrecking themselves and everything else inside the canister. The telescope in question wasn't worth terribly much, at least compared to a Shuttle launch, which at the time cost at least $500 million, not including the cost of any payload, so even if the telescope hadn't been ruined, trying to rescue it wouldn't have made any sense. There were some other satellites in the canister, however, and IIRC, the total value of all the satellites was nothing to sneeze at.

excuse-me 14y ago

Some colleagues of mine had an even worse day. The launch went perfectly but the lens cap released while the Earth was in the IR camera field of view and the entire mission coolant was burned off in a few minutes.

gammarator 14y ago
(WIRE: http://en.wikipedia.org/wiki/Wide_Field_Infrared_Explorer http://en.wikipedia.org/wiki/Wide_Field_Infrared_Explorer)

gammarator 14y ago

(HETE: http://en.wikipedia.org/wiki/High_Energy_Transient_Explorer http://en.wikipedia.org/wiki/High_Energy_Transient_Explorer)

nessus42 14y ago
Yes, that was the one! The two telescopes that I worked on that had no such problems were XTE (aka RXTE) and AXAF (aka Chandra). I only did a little bit of work for AXAF, but I worked on XTE for years. In addition to some other miscellaneous software, I wrote the code that let the scientists configure the parameters of the on-board data processing computers. There were some serious issues with AXAF, though. The CCDs were damaged by some sort of unexpected particle radiation. Prior to this damage, the CCDs on AXAF were the most carefully calibrated CCDs ever manufactured. Or so I was led to believe. And the damage, although not fatal to the mission, did ruin the calibration. This was pretty discouraging to a colleague down the hall, since he had spent years making it so perfect.