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Herschel Space Telescope Opens For the First Time
davecl writes "The Herschel space telescope, the largest ever launched into space, has opened its instrument cover, allowing its three instruments to observe for the first time. BBC news has the main coverage, while there is more coverage on the SPIRE instrument team website, and on the mission blog. I'm part of the SPIRE instrument team and the excitement as we move towards our first observations is building fast. The PACS and SPIRE instruments will see first light in the next few days."
I wonder if they designed any of it to be repaired in space, learning from Hubble. (It's not a direct competitor to Hubble because it "sees" in longer wavelengths.)
I wonder if it would have been cheaper to build *multiple* Hubbles rather than repair them in space, which costs about a half-billion per mission. However, they'd have to decide that path in advanced to take advantage of bulk assembly procedures. Or build them to be remotely serviceable thru a repair-bot? But that's mostly untried technology, which usually means expensive or unpredictable overrun risk.
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Infrared can pass through dust, such as that which composes nebulae, that would block other wavelengths.
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Why do they make Hubble and Herschel sensitive to infrared light? I would think it most important to pick a spectrum that will provide the best information...
Exactly. What spectrum you pick depends on what information you want to get.
Infrared is good for a lot of things. Dust clouds are mostly transparent to infrared, for example, so the infrared is good if you want to look, say, at the nuclei of galaxies (such as our own galaxy) which are surrounded by dust. And if you want to look at galaxies at high redshifts, which is to say, far away (and hence far back in time), infrared is good because the light is shifted into the infrared. Infrared is good at looking for planets, since they emit in the thermal infrared. And many other things.
But if you want to look at gamma-ray bursts from supernovae, no, probably infrared isn't the right way to look. You might want to try the Fermi telescope instead.
It was a static lander, not a rover. And it likely failed because they tried to do it on the cheap. Based on NASA's expenditure-versus-failure history, the amount they spent on it would result in very roughly a 70% chance of failure using the NASA scale. They got what they paid for, I hate to say. They should have scaled it down in my opinion. They got a little carried away with the features, having a small budget. They could have had both more funds and margin for landing reliability if they cut back on weight and instrument-related cost.
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The article mentions the long delay for opening the hatch to wait for outgassing to occur, so the sensors won't get contaminated.
But, don't the pyrotechnic bolts which held the hatch closed (which the article also mentions) outgas, and perhaps even send metallic fragments flying? There is obviously some explosive process involved.
I understand they're more reliable than mechanical latches, but given the need, wouldn't a solenoid operated latch have been better? The hatch would have held closed on its own until in space (since it contained a vacuum), and there's presumably not a lot of force needed to release the hatch once in space.
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