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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

#21

Post by AnimalMuppet »

holler wrote: post #12
tleilaxu wrote: post #8

Earlier quoted context omitted.

Same feelings here! Ever since it was announced I have been anxious about it all going to plan. Sometimes I put myself in the shoes of the engineers and controllers, and I can’t imagine how nerve wracking it must be, waiting and waiting! The thing could simply blow up on the launch pad, for goodness sake!

> The thing could simply blow up on the launch pad, for goodness sake! exactly, I’ve wondered why they don’t build e.g. 2 or 3 of them in tandem since it’d likely be cheaper/easier to do up front vs after the fact if things went wrong. They would then have the additional telescopes if things went right, offering even greater access.

With Mars landers, they do build two of them. When they have an issue with the one on Mars, they break out the one here on Earth and start debugging. When they have a solution that works, then they know what to do with the one on Mars.

I don't know if that would work on telescopes, though - I suspect that the copy wouldn't have the full optics installed.

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

#22

Post by 908B64B197 »

Here's the official release from the launch partner [0](Arianeespace and the Eeuropean Space Agency are providing the launch on an Ariane V rocket).

They are the ones responsible for that milestone of the project (NASA and JPL already completed manufacturing of the spacecraft).

Exciting news!

https://www.esa.int/Science_Exploration/Space_Science/Webb/W...

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

#23

Post by 0xF57A »

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?

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

#24

Post by foota »

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?

I believe there are some kinds of photography that can only be done outside the atmosphere.

Edit: see: https://en.m.wikipedia.org/wiki/James_Webb_Space_Telescope, particularly comparison with other telescopes. Seems the primary reason is for infrared photography.

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

#26

Post by slownews45 »

swarnie_ wrote: post #6
slownews45 wrote: post #4

Does anyone remember the initial proposals for this. The cost was supposed to be $500M. At most something like $1B. Given this is standard govt contracting - I'm sure it's come out much higher.

Fact boy covered it a few weeks ago: https://www.youtube.com/watch?v=CowU0QK0Pjs&ab_channel=Megap... From what i remember this project has been running since around the time of Hubble Still.... Can't wait for it to get up there, money and time well spent!

That's pretty amazing. A financial black hole.

A cool project, but if you think of the thousands of folks who didn't get funding so this thing could gobble everything up - these projects really become crazy budget wise (SLS did the same path).

I wish they would do pay for performance deals. We'll give you $4B if you put a telescope in space of X size that meets some basic specs.

If you look at commercial side, space imaging (earth facing) has just exploded and the cost side has gotten very very good. So it's clear you can get optics and sensing into space for a lot less.

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

#27

Post by jjoonathan »

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?

Maybe MGT isn't limited by diffraction but rather by atmospheric distortion (or residual distortion, because presumably they do what they can to correct it)? Just a guess, I'm not an astronomer.

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

#28

Post by slownews45 »

Jabbles wrote: post #5
slownews45 wrote: post #4

Does anyone remember the initial proposals for this. The cost was supposed to be $500M. At most something like $1B. Given this is standard govt contracting - I'm sure it's come out much higher.

Here is a nice table with the history of the budget: https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Cos...

Clicking through we get this

"JWST is now estimated to cost approximately $9.7 billion and launch in October 2021, which represents cost growth of 95 percent and 88 months of schedule delays since the project’s cost and schedule baselines were first established in 2009."

So around $10B. Amazing.

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

#30

Post by slownews45 »

OrvalWintermute wrote: post #16
slownews45 wrote: post #4

Does anyone remember the initial proposals for this. The cost was supposed to be $500M. At most something like $1B. Given this is standard govt contracting - I'm sure it's come out much higher.

Even 5B for a novel, and uniquely powerful observation platform would be a bargain! When you are engineering a unit of 1 pushing the boundaries of science, with multiple conflicting constraints, funded by a variety of self-interested stakeholders, and are forced to do commercial production, rather than govt production, even when it is most cost effective, it isn't like you are heading towards lowest cost, technically…

You can get a pretty good idea of quality of project management based on how well or poorly they estimated project baseline costs at outset.

These are linked - incompetence in estimating costs / complexity = incompetence in execution = insane cost overruns.

And you would get far more science with 5 $2B projects then one project like this. And if this thing has a launch of deployment problem all eggs in one basket. If there are cost overruns and delays, also all eggs in a basket and no other options.

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