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.

Will Orion be able to service it?

[wisebabo]

So, when the JWST was designed Orion (and the launch vehicles Ares I and Ares V) weren't on the drawing boards.

Does anyone know if Orion will be able to service it? Since it's being designed for flights to the moon, L2 isn't that much further away is it? So the amount of supplies it needs to carry shouldn't be a problem and the reentry capsule should be able to handle the 25,000 mph return. However would the mission be too dangerous in terms of radiation exposure?

Have provisions been made on the JWST since to allow for removal/change of the instruments/gyroscopes like Hubble? What about docking ports or grappling interfaces?

Re:Will Orion be able to service it?

[John Hasler]

> ...having a multi-billion dollar spacecraft dependent on a foreign launch vehicle makes
> me nervous.

That's silly. Ariane V is just as reliable as anything the USA has that could launch the JWST. This is not some Russian war-surplus ICBM or Chinese knock-off of an old US design. It is a mature modern rocket with an excellent launch history.

Re:Will Orion be able to service it?

[khallow]

thanks, also the previous poster (why is the comment hidden) pointed out the wikipedia article on the JWST but it said amongst other things servicing provisions are still under consideration (2008).

From Wikipedia:

NASA is considering plans to add a grapple feature so future spacecraft might visit the observatory to fix gross deployment problems, such as a stuck solar panel or antenna. However, the telescope itself would not be serviceable, so that astronauts would not be able to do things such as swapping out instruments, as has been done with the Hubble Telescope.[18][19][20][21] Final approval for such an addition will be considered as part of the Preliminary Design Review in March 2008.

That's not a serious effort to make the JWST serviceable.

My big fear is that the launch doesn't go successfully, having a multi-billion dollar spacecraft dependent on a foreign launch vehicle makes me nervous. Maybe that's why they fought over the launch decision to use the (free) Ariane V for two years. I'm very happy Kepler went off okay very unhappy about the Orbiting Carbon Observatory.

You do realize that rockets have different capabilities and reliability? The Ariane V is one of the more reliable rockets out there. So is the Delta II that launched the Kepler mission. If you wanted to launch the JWST, currently, you'd need to use either a Proton (can be launched from Kourou, I think), Ariane V (also from Kourou), or Delta IV Heavy (from Cape Canaveral Air Force Station). I don't think other rockets have the payload capability. If I recall correctly, the Ariane V is actually the most reliable of the group (followed by the Proton, Delta IV Heavy just started so it doesn't have a record) I just mentioned. The OCO was launched on a Taurus which doesn't have a good reliability record (one failure in seven launches).

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.

Re:No comment?

[Jeff DeMaagd]

I recall that India, China and Japan have ongoing lunar orbiter missions right now, Japan having an HD feed to earth, I've heard there is a real-time satellite channel that retransmits that feed to any household that tunes to that channel. I can't say much for Russia, I don't recall much from them. Russia gets a lot of money from oil and gas, and the prices aren't what they were in the past couple years.

Hubble may have been a bit too successful, Hubble images have entered mainstream culture in a way few other big science projects have, that is going to be hard to follow. Webb may be a little more obscure given that it's infrared and peering deeper into space, but we'll see.

Re:Build It in Space

[Cally]

Look at the size of that thing. (Seriously, it's absolutely bloody enormous; that's a scale engineering model, with handy nearby humans for scale. Yes, those little black dots on the ground around it are humans... ;) )

Re:Not really a successor?

[Cally]

Well, it's infra-red, but that's pretty close to the spectra of visible light, so the images it produces will be closer to the visual appearance than they do in, say, X-rays. You might also be thinking of the Compton, Chandra or Spitzer space telescopes, which are part of the same programme that gave us Hubble, but are all sensitive to different wavelengths.

Re:Build It in Space

[khallow]

That's not a problem. Once this is built, other projects will present themselves.

And these projects are? The "build it and they will come" argument doesn't work in the complete absence of any knowledge of demand for this sort of thing.

Re:Build It in Space

[khallow]

Once we have the ability to build things like this, we can, among other things, build space probes in orbit.

Why would we want to do that?

This simplifies things because they don't have to have the ability to deploy. It also cuts the mass because all of the equipment used to deploy is used exactly once, but is carried for the rest of the mission. It also means that the probe itself doesn't have to be sturdy enough to withstand launch forces, and that the various components can be reinspected and, if needed, have any launch damage corrected before it sets out.

I don't think this is well thought out. You are weighing the cost of building a satellite in space versus Earth-side manufacture with some special deployment. The latter will win in any near future cost evaluation. It doesn't help that a lot of applications can't get rid of the requirements either for nontrivial deployment processes or high thrust trajectories (see the Oberth effect).

Disappointed, build another scope

[tjstork]

I'm disappointed in the James Webb telescope because:

a) it will be shooting in infrared and that means no visible light details of the planets in our solar system, no pictures of asteroids. Yes, it will help us see stuff billions of light years away, and that's interesting, but what's going on in our solar system is pretty relevant. The easiest way to fix that, of course, is to build a solar system space telescope. Compared to bailing out a bank, I'd much rather have another space telescope.

b) it's named after a bureaucrat, not a scientist. To me, the JWS is right up there with the USS Carl Vinson, John Stennis, and any of the US warships named after presidents. It's just pathetic and sends all the wrong messages.

For christ sakes, if we are going to name it after anybody. I would even prefer naming it after a golden era sci fi writer - Bradbury, Asimov...

Re:Build It in Space

[Doc Ruby]

And for the next 20 telescopes? Vastly bigger and better than any we can build to launch from Earth?

How about the rest of the space industry, like pharmaceuticals, other zero-G/vacuum manufacture, and solar energy collectors, all for returning products to Earth. How about a Lunar base and factory from which to make and launch the rest of what we launch across the Solar System, including to Mars, and outside to interstellar space? A network of comms satellites for science and eventual travel, and perhaps industry among the other planets.

Especially solar power collectors/transmitters would be the next step after we understand the basic science behind space industrial engineering. The value of that, both in the energy and its geopolitical benefits (security, peace, minimal pollution, the pride of getting our of our energy/pollution dead end), is worth quite a lot of investment. Especially with an American or American-led brand on it.

This is the gateway. We are standing on the threshold of projects that are starting to be better performed in space, with the technology to do it. The first project is going to cost way more than that project will return directly. But it will get us started on the much bigger project of industrializing space, with its incalculable returns.

Or we can plod along. And let the military define space industrialization instead of consumer products and energy. Or let rivals like Russia, China or Europe do either - or both - while we're stuck in the 20th Century, in which we made the investments that got those rivals started to pass us.

Re:Build It in Space

[PPH]

Assembling big things in space is a possibility. The ISS is an example. But we need to put people up there to do anything more than the simplest jobs. And we can't even keep our manned programs up to date.

The reason we got stuck with the aging shuttle is that there was no economic justification for the program in the first place. And as a result, no basis upon which to do a cost-benefit analysis (like when airlines scap their L1011s and buy 777s).

Anyway, even when such an analysis is done, its always going to be cheaper to do as much of the fabrication down here on earth. Until a moon base, complete with machine shop, mining and raw materials processing becomes competitive with earth, it'll be done here. Heck, we can't even underbid the Chinese. The moon settlers are going to be bitching about the same inequities. How the earth people undercut their prices, even if shipping costs more.