Hubble Space Telescope is a marvel of astronomical tools - particularly judging by how much it moved the science. It took a lot of fixes along the way, which certainly prolonged its useful life.

Its successor, James Webb Space Telescope, is going to be a significantly better tool. However, it's going to work only for a handful of years, and the reason is "we can't service it" (e.g., to replenish supply of liquid helium). It's going to sit in Earth-Sun L2 libration point, just a few times farther away from Earth than the Moon.

Why we can't service JWST with modern generation of spacecrafts able to fly farther than the Moon? Orion in particular could be a good candidate. Equip it with a propulsion unit - which would cost another launch of a heavy rocket and docking on LEO - and a airlock, which is relatively lightweight and cheap, and you can fly a few weeks mission. Similar capabilities are reachable by other spacecrafts (even with Soyuz, though I doubt it will logistically work to modify it for such an unusual mission). In exchange we'd get longer mission for such a unique tool as JWST promises to be.

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    $\begingroup$ I think there are two parts to this; the servicability of the JWST (I don't think it was built to have bits replaced) and getting there in an Orion spacecraft $\endgroup$ – Dave Gremlin Apr 6 at 19:53
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    $\begingroup$ I doubt you could do this mission for less money than building and launching a JWST replacement. $\endgroup$ – Eugene Styer Apr 6 at 20:29
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    $\begingroup$ Because "Orion" is just an imaginary headline for covering up a multi-billion fraud in the accounting of NASA. Orion was never intended to, and will never, fly. (This might not be apparent to everyone right now, but do check back ten years from now to see that this is true!) $\endgroup$ – LocalFluff Apr 6 at 22:32
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    $\begingroup$ @LocalFluff "never suspect malice when incompetence will answer" $\endgroup$ – Organic Marble Apr 7 at 0:41
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    $\begingroup$ @LocalFluff - The blame for this fraud lies more with Congress than with NASA. A better way to look at it: Orion (along with the SLS) is a multi-billion fraud in the accounting that Congress has foisted upon NASA. $\endgroup$ – David Hammen Apr 7 at 9:43

James Webb Space Telescope Program Scientist Dr. Eric Smith spoke about this on TMRO recently. The main reason is that the telescope wasn't designed to be serviced so it is not as modular as Hubble and systems are integrated throughout the telescope rather than being discrete units that can be removed and replaced like on Hubble. It was designed like this from the beginning because they knew it would be at L2 rather the LEO where it would be much more difficult to service.

That being said they did include optical targets on the bottom of of the telescope where the fuel ports are so a mission in the future could potentially come and refuel it. I don't know if that is something that Orion could potentially do but I wouldn't think a manned mission would be required for a refuel and if it's not manned why use Orion.

  • $\begingroup$ Accepted. At the same time the main limitation on the service life is said the helium limit, which should be relatively easy to transfer. And not being modular could be actually harder to achieve (modularity allows, for example, parallel development and less dependencies of systems on each other), even though it's more optimal for size and weight. Would be interesting to learn about development process of JWST in another thread. $\endgroup$ – Space Arris Apr 7 at 15:29

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