4 ms·

A combination of space engineering costs being habitually lied about in proposals and the conventional space industry being about half science, half jobs progra

A combination of space engineering costs being habitually lied about in proposals and the conventional space industry being about half science, half jobs program. Frankly I wish someone would do an article on the "long tail" possibilities for Webb. Can it do a warm mission after its refrigerant runs out like Spitzer? Does it have low-bandwidth long range communications for when it runs out of fuel and falls out of L2? I feel like we're just supposed to be ok with a ten billion dollar telescope only lasting a decade.

pkaye 5y ago
Only one instrument the MIRI needs active cooling. Rest is all passive cooling. It has a closed loop cooling system so it will not run out of refrigerant. Once it runs out of fuel it will eventually drift out the L2 point and might lose orientation. They feel they can stretch the mission up to 20 years with the saved fuel. There is a port for refueling the craft in the future but the technology needs to built.
- causality0 5y ago
  Why would it lose orientation? It has reaction wheels.
  - racnid 5y ago
    The simple answer is that you eventually have to do thruster burns to dump momentum from reaction wheels; they can't keep absorbing momentum forever. It also needs the fuel to adjust it's orbit every so often and keep it on station.
GuB-42 5y ago
The question is "is it worth it?". New scientific instruments usually come with a bunch of discoveries, because we are now able to see what we couldn't see before, but there are diminishing returns, because we run out of interesting things to look at. Some platforms can be upgraded, like the ISS, ground based telescopes, and Hubble in 2009, so that new science can be done, but it is not the case for JWST. So I suspect that there will not be much left to do with it after 10 years, especially if it is not fully operational. It will not be completely useless, but I expect money to be better spent making a new instrument, with better technology and guided by the latest discoveries, than trying to extend the life of an aging instrument that has given most of what it could give.

pkaye 5y ago

Only one instrument the MIRI needs active cooling. Rest is all passive cooling. It has a closed loop cooling system so it will not run out of refrigerant. Once it runs out of fuel it will eventually drift out the L2 point and might lose orientation. They feel they can stretch the mission up to 20 years with the saved fuel. There is a port for refueling the craft in the future but the technology needs to built.

causality0 5y ago
Why would it lose orientation? It has reaction wheels.
- racnid 5y ago
  The simple answer is that you eventually have to do thruster burns to dump momentum from reaction wheels; they can't keep absorbing momentum forever. It also needs the fuel to adjust it's orbit every so often and keep it on station.

GuB-42 5y ago

The question is "is it worth it?". New scientific instruments usually come with a bunch of discoveries, because we are now able to see what we couldn't see before, but there are diminishing returns, because we run out of interesting things to look at. Some platforms can be upgraded, like the ISS, ground based telescopes, and Hubble in 2009, so that new science can be done, but it is not the case for JWST. So I suspect that there will not be much left to do with it after 10 years, especially if it is not fully operational. It will not be completely useless, but I expect money to be better spent making a new instrument, with better technology and guided by the latest discoveries, than trying to extend the life of an aging instrument that has given most of what it could give.