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James Webb is fully deployed

nasa.gov

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Re: James Webb is fully deployed

#111

Post by bumby »

sailingparrot wrote: post #102
WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

Because it's a wrong assumption. Significant cost come from the assembly and testing of all the components itself, that you would have to redo entirely. Also if you were to build just 2 or 3 of them, you can't expect any economy of scale. On top of that, the operational cost of JWST is expected to be around 1B$ for it's lifetime, you could expect that to be similar for every single replica you have. And finally, you…

This question comes up in every one of these threads and this is the correct response.

If you look at the line items on a build, you might see something like a $200 bolt. It’s not that there was $198 of R&D going into the design of the bolt, it’s that quality management drives the cost. Chain-of-custody, bonding, material testing, witnessing etc. are all part of that effort and they don’t scale like a design spec does.

Re: James Webb is fully deployed

#112

Post by mrtnmcc »

alimov wrote: post #92
Server6 wrote: post #87

Earlier quoted context omitted.

Why would we need two? I would think the next one 20+ years from now would hopefully be exponentially better.

So that more researchers have access. Afaik access is shared and researchers have to make a proposal and get it approved before use, which to me suggests some kind of queue

Queueing researchers should be fine given the universe will be around for a while.

Re: James Webb is fully deployed

#113

Post by asteroidbelt »

kitd wrote: post #109
asteroidbelt wrote: post #103

No mention of ESA again, looks like it is solely NASA project, which it is not. Shame.

I was under the impression that ESA's role was to get it into orbit, and is thus largely done. Is that wrong?

From Wikipedia:

> NIRSpec (Near InfraRed Spectrograph) will also perform spectroscopy over the same wavelength range. It was built by the European Space Agency at ESTEC in Noordwijk, Netherlands.

and more.

Re: James Webb is fully deployed

#114

Post by _Microft »

WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

Why spend money on JWST 2 when you could as well spend it on ... LUVOIR? ^^

https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr...

Re: James Webb is fully deployed

#115

Post by BurningFrog »

Server6 wrote: post #87
WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

Why would we need two? I would think the next one 20+ years from now would hopefully be exponentially better.

To get twice the science done, of course.

Re: James Webb is fully deployed

#116

Post by ajuc »

Server6 wrote: post #87
WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

Why would we need two? I would think the next one 20+ years from now would hopefully be exponentially better.

In 10 years we can send a bigger, simpler, cheaper, one-piece, non-foldable telescope in Starship for a fraction of the cost. The biggest saving wouldn't even be the launch costs - it would be the simple design allowed by relaxing the volume and mass constraints.

Re: James Webb is fully deployed

#117

Post by [deleted] »

davesque wrote: post #91
emptyfile wrote: post #60

Amazing feat of engineering. NASA can be proud of achieving something that no other space agency could do. It took courage to keep shovelling money and effort into this project and some amazing science to get it deployed into space.

I agree with the sentiment, but I think some people might take issue with the suggestion that this was entirely NASA's achievement.

[deleted]

Re: James Webb is fully deployed

#118

Post by ajuc »

loonster wrote: post #107
WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

The Hubble telescope wasn't unique. It was simply the first one that was pointed away from earth. For the JWST, is there even room for a 2nd telescope at L2?

There's room for a lot of them, it will be in orbit around L2, not exactly in L2.

Re: James Webb is fully deployed

#119

Post by WalterBright »

sailingparrot wrote: post #102
WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

Because it's a wrong assumption. Significant cost come from the assembly and testing of all the components itself, that you would have to redo entirely. Also if you were to build just 2 or 3 of them, you can't expect any economy of scale. On top of that, the operational cost of JWST is expected to be around 1B$ for it's lifetime, you could expect that to be similar for every single replica you have. And finally, you…

Assuming your figures are correct, you'll get double the data for another 30% cost.

If you wait a month before launching #2, if problems appear in #1 (like the telescope mirror was ground improperly) it can be fixed in #2.

The operational cost will not double. The same ground facility, equipment, and staff can manage both.

If you're buying two identical launches, you can get a quantity discount.

> the benefits of a second one would be marginal compared to the benefits of the first one

And yet I read many glowing accounts about how much extra value came from extending the Hubble's lifetime.

I do have some experience with this. I worked for 3 years on the design of the 757. Thousands of engineers spending maybe 5 years on it. None of that has to be repeated. In a machine shop, most of the cost is in the setup. Making two adds little cost. I had a job assembling electronics to help pay for college. The first board would take 2 hours to build. The next one, half that. The fourth, 20 minutes.

I'm sure there's plenty of software on board that machine. On HN we all know how expensive making software is. Making a copy costs nothing.

Re: James Webb is fully deployed

#120

Post by WalterBright »

bumby wrote: post #111
sailingparrot wrote: post #102

Earlier quoted context omitted.

Because it's a wrong assumption. Significant cost come from the assembly and testing of all the components itself, that you would have to redo entirely. Also if you were to build just 2 or 3 of them, you can't expect any economy of scale. On top of that, the operational cost of JWST is expected to be around 1B$ for it's lifetime, you could expect that to be similar for every single replica you have. And finally, you…

This question comes up in every one of these threads and this is the correct response. If you look at the line items on a build, you might see something like a $200 bolt. It’s not that there was $198 of R&D going into the design of the bolt, it’s that quality management drives the cost. Chain-of-custody, bonding, material testing, witnessing etc. are all part of that effort and they don’t scale like a design spec doe…

If it's a one-off bolt with a custom design, it will likely cost thousands of dollars.
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