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The James Webb Space Telescope has passed the final mission analysis review

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Re: The James Webb Space Telescope has passed the final mission analysis review

#101

Post by cromwellian »

wolverine876 wrote: post #85
cromwellian wrote: post #83

I feel like this is an all-eggs-in-one-basket mission. If it fails to launch, we have nothing. Why not build many JWSTs, surely the cost per unit would go down, and launch more than one?

> surely the cost per unit would go down, and launch more than one? Surely? They didn't build a JWST factory. It might go up, as people with specialized skills or knowledge have moved on.

Yes, surely. Most of the cost was in R&D and in the mirror manufacturing. They've been designing and manufacturing it for 20 years. Per-unit costs would go down. Take the mirror, it's made of segments, the facility used to produce those segments certainly would benefit from scaling up production. They'd get better at fabbing them over time, increasing yields, reducing costs.

What NASA is doing is building the equivalent of a $10 billion fab to produce one chip. Space telescopes could be continually produced on a schedule, and retired on a schedule, with constant improvement.

Look at RS-25 engines vs Raptor engines in terms of costs to produce one.

Re: The James Webb Space Telescope has passed the final mission analysis review

#102

Post by wolverine876 »

bronson wrote: post #31
0xF57A wrote: post #23

I was watching a presentation given by the MGT project manager at cal tech and he mentioned that the MGT has a lower diffraction limit than the JWST. I think “diffraction limit” was the term he used, I don’t remember. The idea was that the images are supposed to be sharper. I was very confused about that. Why build JWST if MGT is going to maker cleaner images?

MGT is limited to the light that filters through the atmosphere. JWST will be tuned to longer wavelengths (redshifted older objects) that can only be seen in cold space.

> JWST will be tuned to longer wavelengths (redshifted older objects) that can only be seen in cold space.

As I understand it: We're placing it at L2 specifically for that reason, to isolate it from other radiation.

Re: The James Webb Space Telescope has passed the final mission analysis review

#103

Post by jasonwatkinspdx »

endymi0n wrote: post #69

While it‘s awesome to finally see the JWST finally come to close to launch after all those years, now it‘s a close race between it and SpaceX Starship that could have taken the 6.5 meter mirror up to space in one whole piece in its 9m diameter belly rather than having to do all the miraculous origami that took two decades to develop in the first place…

While I'm rooting for SpaceX with Starship, lets be clear: they're still trying to get hovering grain silo versions working. Meanwhile JWT is ready to go. If it's a race one side has already won rather emphatically.

Re: The James Webb Space Telescope has passed the final mission analysis review

#104

Post by BitwiseFool »

wolverine876 wrote: post #82
BitwiseFool wrote: post #60

Earlier quoted context omitted.

The JWST orbits out beyond the Moon, so I don't know if the Orion capsule and European Service Module even has the Delta-V to make it to that Lagrange point and back. Plus, I'm also unsure about the life support and duration requirements for such a mission. I imagine the only realistic repair mission would be with a Starship crew, seeing as Orion and all the other Commercial Crew vehicles would probably require some…

The GP asked about robotic, not human missions.

My mind skipped over that. I don't have a good answer for a robotic mission but I imagine NASA won't fund it.

Re: The James Webb Space Telescope has passed the final mission analysis review

#106

Post by chorsestudios »

cromwellian wrote: post #83

I feel like this is an all-eggs-in-one-basket mission. If it fails to launch, we have nothing. Why not build many JWSTs, surely the cost per unit would go down, and launch more than one?

The cost per unit would probably remain around the same. You don’t really get price cuts for ordering 2 of a custom component instead of 1

Re: The James Webb Space Telescope has passed the final mission analysis review

#107

Post by wolverine876 »

cromwellian wrote: post #101
wolverine876 wrote: post #85

Earlier quoted context omitted.

> surely the cost per unit would go down, and launch more than one? Surely? They didn't build a JWST factory. It might go up, as people with specialized skills or knowledge have moved on.

Yes, surely. Most of the cost was in R&D and in the mirror manufacturing. They've been designing and manufacturing it for 20 years. Per-unit costs would go down. Take the mirror, it's made of segments, the facility used to produce those segments certainly would benefit from scaling up production. They'd get better at fabbing them over time, increasing yields, reducing costs. What NASA is doing is building the equival…

Increasing production from 1 unit to 2 doesn't necessarily reduce costs. Due to demand and limited supply, for example, some prices increase. We know almost nothing about this thing. It's very speculative to say the cost would decrease. Also, how many space telescopes of this variety do we need?

All that said, it would be interesting to see NASA research on mass producing the more common components of its 'product line'. It does it for rockets, of course, but computers? Solar panels? Mars rover components? I'm sure it's been considered and I expect it's done in ways I'm not aware of.

Re: The James Webb Space Telescope has passed the final mission analysis review

#108

Post by dgrant »

wolverine876 wrote: post #85
cromwellian wrote: post #83

I feel like this is an all-eggs-in-one-basket mission. If it fails to launch, we have nothing. Why not build many JWSTs, surely the cost per unit would go down, and launch more than one?

> surely the cost per unit would go down, and launch more than one? Surely? They didn't build a JWST factory. It might go up, as people with specialized skills or knowledge have moved on.

I think the verb tenses were not perfect... I think he just meant: why did they build only 1 in the first place? They could have built N instead, at a lower cost per unit.

Re: The James Webb Space Telescope has passed the final mission analysis review

#109

Post by imglorp »

geenew wrote: post #57
jl6 wrote: post #54

If the JWST survives launch but has a subsequent mechanical problem that prevents it deploying properly (and it’s the kind of problem that would have been fixable on Hubble, using a shuttle mission) would it be feasible to mount a robotic rescue mission to chase it down and remote-hands it back to life? For less than the cost of just launching another JWST?

It has a docking clamp, though that's for future-proofing. Apparently the initial type of mission envisioned was a crewed Orion vehicle, though I'm sure a wide variety of missions could attach. My guess was that the clamp was mainly for possible future replenishment of consumables, though presumably some sort of robotic-arm-equipped repair mission could attach as well. A crewed mission seems possible, too, assuming o…

Nothing in the current fleet of new capsules have arms or airlocks.

There is hope for the robotic refueling type mission though, or at least the kind where a new utility bot attaches to an old satellite and takes over propulsion to extend its life.

https://nexis.gsfc.nasa.gov/rrm_refueling_task.html

Re: The James Webb Space Telescope has passed the final mission analysis review

#110

Post by redisman »

mongol wrote: post #53

What is it hoped this can see? Is there some specific hypothesis this telescope was built to confirm?

The oldest galaxies that have red shifted off the spectrum and are only visible with this. You can’t do IR telescoping except at L2 because earth is giving off its own IR reflection or radiation or something like that
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