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Comment by asplake | Hacker News Reader

Tempting fate perhaps even to ask, but I wonder if an unmanned refuelling mission might be possible?

There is a very good and detailed answer to your question here: https://space.stackexchange.com/questions/38389/is-it-possib...

That's a very good answer. A few more points, because the answer is a 2.5 years old.

- the docking adapter discussed in the answer did not make it. However, the answer offers a couple of alternatives, so +1.

- they painted some crosses on the JWST to make alignment easier.

- JWST's L2 location is really far from Earth. It's about 4X the distance from the moon. So a manned mission is currently infeasible. But maybe in the future.

- while fueling may be possible, any other sort of maintenance probably isn't. To save weight, the JWST is mostly glued together, unlike Hubble which used spacesuit accessible bolts.

It's also worth noting that much of JWST is now twenty year old technology. Assuming it isn't a total failure which needs to be salvaged for PR reasons, it will almost certainly make more sense to build a new observatory in ten years rather than rescuing this one. If Starship exists at that point it will also be a much less complex undertaking to get it into space, and it could likely use an even bigger mirror.

The complexity of the undertaking was not building the rocket. The complexity is the telescope itself. It would be interesting what the costs come down to if rather than starting from scratch they iterated on existing designs. Anyone know what the incremental cost of building the same telescope again would look like?

My understanding is that a lot of the complexity is making the telescope able to fit in limited space and then unfurl. That constraint is lifted significantly with Starship.

I think that the other commenter was referring to the relative complexity in JWST's unfolding/deployment. It might be possible to deploy something from Starship that doesn't need to be packed as tightly (and save on engineering costs there) and still get around the same performance.

A complicated sunshield deployment seems somewhat inevitable, personally, but I'd be happy to be proven wrong there.

> So a manned mission is currently infeasible. But maybe in the future.

Given the increased interest in manned missions and recent technology advancements/investments, I wouldn't be surprised if we could get there in 15-20 years, which sounds likely to be when it'd need to be refueled.

If it's worth it or too dangerous to send an astronaut to deal with the dangerous refueling operation are whole other questions. But actually getting there? I think we can do it in 15-20 years.

Maybe but it might be obsolete by then, especially considering how much lift capacity Starship will bring online. Will be a lot cheaper to just replace Webb.

It sounds like the main cost (time & $$$) with the Webb was R&D, not the actual launch. Am I wrong?

The main cost was testing. Another big cost was tooling, much of which has been lost.

I've read that optical tracking/docking markers were added around mating ring that connected JWST to Ariane upper stage. It does not mean that docking to it will be easy but it was at least considered.

Physics doesn’t make this impossible, but it’s _enormously_ expensive to get payload to L2.

I am not familiar with the station keeping needed for maintaining an L2 orbit; would it be possible to use an Earth orbiting laser to apply photonic force against JWST's solar shield (turning it into a laser sail) to balance it "falling back" towards Earth without onboard propellant? My understanding is that it has a gravitational weighting towards Earth to prevent slipping away.

Is it enormously expensive because of physics or because of bureaucracy and politics?

Like, serious question: how much cost are the raw materials for the fuel and spacecraft/rocket, and how much are the costs like human labor and ground transportation to the launch site?

They are planning one!

Source?

Reply on news.ycombinator.com