7

Everybody is super nervous about possible hiccups or, goodness forbid, failure modes of the telescope. It is a fairly complicated machine.

The telescope will be at the second Lagrange point, several light seconds away from Earth, about five times as far as the Moon. But then L2 is not a gravity well so that no descend vehicle is needed; all that is needed is a launch system and a spacecraft that have enough capacity for the crew, material and fuel needed to stop and return, and that can keep the crew alive long enough for a return trip.

Is there a theoretical possibility for a manned mission to reach that point with existing launch systems and spacecraft, possibly after ad-hoc modifications? (I'm aware that NASA says it is not an option but we are more agile and inventive than that, right?)

I suppose StarShip, potentially with minor modifications, could do the job hands down; anything before that?

Peter - Reinstate Monica
  • 2,181
  • 14
  • 25
  • IMO Orion+Crew is sooner than Starship+Crew, though I don't know if Orion+ESM (+EUS?) has the juice to kick it all the way to L2. – BrendanLuke15 Dec 15 '21 at 13:26
  • 2
    Putting people on an untested mission profile has much worse options for failure. – SE - stop firing the good guys Dec 15 '21 at 13:48
  • @SE-stopfiringthegoodguys Every mission profile has a first flight. I suppose the crew are volunteers. (Sorry to sound so dismissive -- surely there are above average risks, and a cost/benefit analysis should be made. And then, shuttle flights were not exactly safe either.) Also, once the basic capabilities are assured, there are no orbit insertions, no rendez-vous with coupling, no landings -- as missions go, it would be pretty straight forward. – Peter - Reinstate Monica Dec 15 '21 at 13:52
  • 2
    It boils down to: is it worth it? If it fails prematurely, I bet that a replacement will cost less, takes less time to build (and use more state-of-the-art technologies) than a platform designed 20 years ago. – Ng Ph Dec 15 '21 at 13:58
  • @NgPh The economies of such a mission are an interesting point. On the other hand the telescope is a major tech achievement (I mean it's been 25 years in the making, right?); replicating it (minus the flaw) would probably be a better bet than redesigning it. Obviously one would then need a launch to L2 anyway, although a smaller one than for a returning crew. – Peter - Reinstate Monica Dec 15 '21 at 14:01
  • 4
    Orion doesn't have an airlock or an arm. – Organic Marble Dec 15 '21 at 14:16
  • @OrganicMarble Haven't we done fairly significant EVA work (Apollo and Skylab) with neither? – ikrase Dec 16 '21 at 06:20
  • @ikrase Without an airlock? I wasn't aware of that, interesting. – Peter - Reinstate Monica Dec 16 '21 at 06:53
  • @Peter-ReinstateMonica Apollo never had an airlock -- we did both the moonwalks, and an EVA in which an astronaut crawled along the outside of the CSM to retrieve recording media from instruments in the CSM. I don't remember the details of Skylab but it's my impression we did repair work without using an airlock at least for part of it/ – ikrase Dec 16 '21 at 06:55
  • 1
    @ikrase A list is here and an account of Moon and "transearth" EVAs here. Apparently, an EVA was necessary to retrieve film: "In order for the exposed photographic film from these cameras to be returned to Earth for processing and analysis, an EVA had to be performed to remove them from the SIM and stow them inside of the CM with the crew." – Peter - Reinstate Monica Dec 16 '21 at 07:52
  • 1
    @ikrase if by 'significant' you mean Hubble-like repairs with multi-day multi-EVA on a satellite that was rndz'd with and captured by the repair vehicle - then no. Skylab was a space station, lunar EVAs are hardly comparable. – Organic Marble Dec 16 '21 at 12:38
  • 1
    "but we are more agile" haha! in '61 Kennedy proposed moon landing and we were there by '69. the return to the moon was announced in '17, we'll be very very lucky to accomplish it in the same timeframe. the short answer is no. the hubble was designed to be serviceable in the bay of the shuttle, JWST is not designed to be serviceable and there's no ship with a repair bay. if it was a "humanities existence depends on it, spare no expense and who cares if the crew returns!" type situation then maybe (if all we have to do is hit it with a wrench), but nothing is going to happen over a $10B sat. – eps Dec 17 '21 at 06:55
  • @eps Well, "we" referred to the perusers of and contributors to space SE, not today's NASA as an institution ;-). Ad rem: Well, 10B gets you quite a few launches these days, let alone the 25 years of prep down the drain because of a stuck hinge, for example. So yes, the premise is that the repair/maintenance can be done without a bay. There must be an entire class of failure modes that don't respond to wiggling (what JWT can do itself) but to a wrench. Whether Starship or another large craft could "simply" take it home (sans sunshield) is another question. – Peter - Reinstate Monica Dec 17 '21 at 08:10
  • See also https://space.stackexchange.com/q/57355/27141 – Stilez Dec 25 '21 at 16:00

1 Answers1

5

On Christmas day, the New York Times reported that indeed NASA officials were thinking about service missions, which could be robotic rather than manned:

But should a problem arise that would require repair, a robotic spacecraft could be sent to get the job done, Pam Melroy, NASA’s deputy administrator, said in an interview.

“Have we talked about it? Oh yes we have talked about it,” said Ms. Melroy, whose previous job leading the tactical technology office at DARPA, the Pentagon’s research and development agency, made her a “big fan of robotic servicing.”

“I think we could actually put something together that would allow us to send a refueler or a servicer out there,” she said. “It might take a few years to pull all that together.”

Peter - Reinstate Monica
  • 2,181
  • 14
  • 25
  • Now IF ONLY the JWST had been designed with serviceability in mind. – CuteKItty_pleaseStopBArking Dec 25 '21 at 16:30
  • 2
    @CuteKItty_pleaseStopBArking Well, an additional feature, even if it is maintainability, will add complexity and must be balanced against other design goals. A laser sharp focus to get one single thing right may improve your odds to succeed. – Peter - Reinstate Monica Dec 25 '21 at 19:37
  • That is a (false) argument that can be used to claim that all redundancy, spares, fallbacks and failsafes are to be avoided. Designing for serviceablility would not make the project more likely to fail. It would necessarily add some mass to the end product. – CuteKItty_pleaseStopBArking Dec 26 '21 at 08:23
  • @CuteKItty_pleaseStopBArking I think it's an argument that Elon Musk makes. Maybe he is focusing more on weight, but I think reduced complexity also plays a role in hie design principle of simplicity. My partner sitting next to me, designing pacemakers, nods: If you can simply weld things together it's one failure mode less compared to screwing or snapping. – Peter - Reinstate Monica Dec 26 '21 at 15:57
  • As of about 4 years ago, the plan was to have a docking point on JWST, in case of a future servicing capability. I haven't otherwise since. – Vince 49 Dec 27 '21 at 08:38