4 ms·

It's also going out pretty far (the L2 Lagrange point on the other side of the moon), so they also won't be able to perform any manned post-launch repair missio

It's also going out pretty far (the L2 Lagrange point on the other side of the moon), so they also won't be able to perform any manned post-launch repair missions like they did with Hubble.

guerrilla 5y ago
Actually I have a question about this. What happens if it fails at L2? Is that position like occupied or more difficult to deal with from then on?
- huntsman 5y ago
  The L2 point is unstable do energy needs to be expended to maintain position there.
- Out_of_Characte 5y ago
  Solar wind will push it out of L2 and into an orbit around the sun. This is already going to happen once JWT runs out of fuel to maintain its position.
messe 5y ago
> so they also won't be able to perform any manned post-launch repair missions like they did with Hubble. In terms of hardware that's readily or soon to be available, it is technically possible. Starship, if it gets off the ground, is the obvious choice. Orion could do it, but it would mean dumping another two billion into JWST. If it really came down to it, Falcon Heavy launched with a Crew Dragon sitting on top of it could probably reach it, although it might need an additional kick stage (I haven't done the maths), and it would need to be crew rated first (and SpaceX don't currently have an interest in doing that).
- bumby 5y ago
  If you consider the human to be part of that hardware, it's over 4x the distance that a human has ever travelled. There would still be a lot of technical problems to be figured out.
- gaius_baltar 5y ago
  Having a ship and a launcher capable of reaching the telescope is a bit different of being able to service it. I understand that just planning and preparing a mission on this scale, with current technology and processes, would take more time than the service life of the telescope itself. Also, AFAIK, Crew Dragon does not have airlocks or other resources for EVAs. Not sure it the capsule can be evacuated for that too. But I would like more information in this issue ... could not find too much from reliable sources for now.
  - messe 5y ago
    > Having a ship and a launcher capable of reaching the telescope is a bit different of being able to service it. True. But generally when people bring up the statement that we can't service it, they usually back that up by citing the distance. There would still be a lot of hurdles to overcome, but none are insurmountable with relatively small investment. All of that said, if Starship works, then the economics change drastically anyway. You could probably launch an entire fleet of less reliable, but much cheaper telescopes, for less than the cost of servicing.
bewaretheirs 5y ago
Webb is going to the Sun-Earth L2 (about 1.5 million km from Earth), not the Earth-Moon L2 (which is about 61,000 km from the Moon and 445,000 km from the Earth. https://webb.nasa.gov/content/about/orbit.html https://webb.nasa.gov/content/about/orbit.html

It's also going out pretty far (the L2 Lagrange point on the other side of the moon), so they also won't be able to perform any manned post-launch repair missions like they did with Hubble.

guerrilla 5y ago

Actually I have a question about this. What happens if it fails at L2? Is that position like occupied or more difficult to deal with from then on?

huntsman 5y ago
The L2 point is unstable do energy needs to be expended to maintain position there.
Out_of_Characte 5y ago
Solar wind will push it out of L2 and into an orbit around the sun. This is already going to happen once JWT runs out of fuel to maintain its position.

messe 5y ago

> so they also won't be able to perform any manned post-launch repair missions like they did with Hubble. In terms of hardware that's readily or soon to be available, it is technically possible. Starship, if it gets off the ground, is the obvious choice. Orion could do it, but it would mean dumping another two billion into JWST. If it really came down to it, Falcon Heavy launched with a Crew Dragon sitting on top of it could probably reach it, although it might need an additional kick stage (I haven't done the maths), and it would need to be crew rated first (and SpaceX don't currently have an interest in doing that).

bumby 5y ago
If you consider the human to be part of that hardware, it's over 4x the distance that a human has ever travelled. There would still be a lot of technical problems to be figured out.
gaius_baltar 5y ago
Having a ship and a launcher capable of reaching the telescope is a bit different of being able to service it. I understand that just planning and preparing a mission on this scale, with current technology and processes, would take more time than the service life of the telescope itself. Also, AFAIK, Crew Dragon does not have airlocks or other resources for EVAs. Not sure it the capsule can be evacuated for that too. But I would like more information in this issue ... could not find too much from reliable sources for now.
- messe 5y ago
  > Having a ship and a launcher capable of reaching the telescope is a bit different of being able to service it. True. But generally when people bring up the statement that we can't service it, they usually back that up by citing the distance. There would still be a lot of hurdles to overcome, but none are insurmountable with relatively small investment. All of that said, if Starship works, then the economics change drastically anyway. You could probably launch an entire fleet of less reliable, but much cheaper telescopes, for less than the cost of servicing.

bewaretheirs 5y ago

Webb is going to the Sun-Earth L2 (about 1.5 million km from Earth), not the Earth-Moon L2 (which is about 61,000 km from the Moon and 445,000 km from the Earth. https://webb.nasa.gov/content/about/orbit.html https://webb.nasa.gov/content/about/orbit.html