John Mather On the Building of the James Webb Space Telescope

Nancy Atkinson writes "Why is the James Webb Space Telescope (scheduled to launch in 2013) taking so long to build? Hasn't it had a huge cost over-run and several delays? Nobel Prize winner John Mather is the Project Scientist for JWST, and he addresses these questions and more in an in-depth interview, one of the few he's given about this next-generation telescope and successor to the Hubble Space Telescope. Quoting: 'The hardest thing to build was the mirror, because we needed something that is way bigger than Hubble. But you can't possibly lift something that big or fit it into a rocket, so you need something that is lighter weight but nonetheless larger, so it has to have the ability to fold up. The mirror is made of light-weight beryllium, and has 18 hexagonal segments. The telescope folds up like a butterfly in its chrysalis and will have to completely undo itself. It's a rather elaborate process that will take many hours. The telescope is huge, at 6.5 meters (21 feet), so it's pretty impressive.'"

Comments

Re:Build It in Space

[PPH]

Because tooling and equipment needed to build it weight many orders of magnitude more than the telescope.

Re:Build It in Space

[ogre7299]

The problem with this idea is that you will have to send people to put it together. And you still need to launch all the pieces.

So you'll have combined cost launching the pieces and people. Whereas building it on earth, you have all the engineers to put it together and then put it up all in one shot.

Until there is a manufacturing base out in space which probably will not happen for a long long long time, you still have to design and test everything on the ground. This is because you can't afford to launch a faultly part, this is true if you are sending the whole thing up or putting it up in pieces.

Re:Build It in Space

[khallow]

1. We don't know how to do that yet and we don't have the infrastructure to support it. Lunar manufacturing facilities capable of building state of the art telescopes are well beyond our reach.
2. If assembly in orbit, all material would be supplied from Earth. Too expensive at near future launch costs.
3. Not enough demand. Only one space telescope.
4. Requires a lot of testing and inspection by humans on site.
5. Lunar manufacture of telescopes not much of an improvement over Earth-based manufacture. Same gravity problems. There is some benefit to putting stuff in Earth orbit with lower delta v and no Earth atmosphere to interfere. But a space telescope would be a high value per weight item and hence something that can be competitively lauched from Earth.

Aerospace is incentivized to be over budget

[skoda]

Those who denigrate aerospace projects for being over budget and over schedule are either naive or disingenous.

The unfortunate reality is aerospace companies are strongly motivated by the Federal Gov't proposal selection process to bid too low and too fast for high-risk projects like JWST. While not truely "lowest cost" bidder selection, it's understood that a winning bid will be in a certain range, regardless of whether its realistic. And the schedule proposals must also target certain bogies to have a chance of winning, regardless of winning.

And so companies bid low and fast to meet the proposal expectations and requirements, knowing that they'll make it up in cost-plus overruns as the Program proceeds.

And those running the programs know this too.

And ultimately, each project such as JWST is a one-of-a-kind endeavor. New technologies, new manufacturing methods, new test techniques are invented during the course of the project. It's difficult to predict the budget and schedule for doing something never done before; much less keeping to an optimistic budget driven by political needs more than the technical.

To those on JWST, they are doing incredible work, putting in long hours, and coming up with creative solutions to very challenging problems. And everyone of them wants to see JWST succeed.

No comment?

[gammaraybuster]

I had to reply to this thread, seeing only 9 hidden comments so far. That's a bit sad, since the JWST will be one of the most important science events since the Hubble. It will be an infrared telescope like the Spitzer, but it will effectively be an optical telescope for the distant universe because of red shift! And it will be able to peer into the distant past unlike any telescope prior.

In the sense of being a "space race" this is one area where the US really shines. There's no other nation that really is in the running, although there are lots of international contributions (yay Canada!). Maybe it's because of the language barrier, but I can't think of a single Russian space telescope. I can name a half dozen US scopes and one or two from the ESA. (Be sure to look up the Chandra, Fermi, Spitzer, XMM-Newton)

But then it's not really a space race, it's about science, so maybe it's a little boring for the general public. I only hope Slashdotter's are more aware that this is one of the great scientific adventures of our time.