Tag: James Webb Space Telescope

James Webb Space Telescope's primary mirror is ready to go!

By Phil Plait | August 20, 2012 6:30 am

The James Webb Space Telescope – NASA’s successor to Hubble – recently reached a pretty big milestone: all of the segments of its primary mirror have completed construction, and are ready to be handed over to NASA.

JWST isn’t your average ‘scope. Instead of a single, monolithic mirror, it will have 18 hexagonal segments that will fit together, working as a unit to focus infrared light from distant astronomical objects. Each segment is about 1.5 meters across, and will have actuators behind them (think of them as very accurately tunable pistons) to control exactly how the submirrors are aimed. On the front, each mirror is coated in a very thin layer of gold, which is an excellent reflector of IR light.

The mirrors were made at the Ball Aerospace facilities in my hometown of Boulder, Colorado. Ball threw a celebration to mark the mirrors’ completion, and invited a few press folks along. That included me! We went on a tour, and saw one of the mirrors – it was in a "clean room" to keep dust and other contaminants out. But we could see it through a door… and here it is:

Yes, that’s me reflected in one of JWST’s flight mirrors! That was pretty cool. [Click to embiggen.]

Looking a picture of a mirror can be difficult when you’re trying to see the mirror itself. Here’s another shot that makes it more obvious.

The mirrors is tilted up, and the dark band running through it is the reflection of the top of the stand it’s mounted in. Their mirror itself is the gold hexagon. I got a good look at it, and it’s no small thing for me to say its the cleanest mirror I’ve ever seen. I’ve been around a few ‘scopes in my time and their mirrors always have some schmutz on them. This had none.

The figure of each mirror (the technical term for the shape of the surface) is incredibly accurate: the bumps in the surface are on average smaller than 25 nanometers. A nanometer is a billionth of a meter… to give you an idea of how small this is, a typical human hair is 400 times thicker than the deformities in the mirror. As one person mentioned to me while we were gawking at the facilities, if a bacterium fell on the surface, it would far and away be the biggest thing on the mirror.

So yeah, these things are smooooth.

The mirrors need to be this smooth to accurately reflect light. Any nonconformity would scatter light a little bit, messing up the telescope’s resolution. I’ll add that mirrors like this – the size they are, made of beryllium, figured to this accuracy – have never been accomplished before. And that’s only part of it, since of course all 18 mirrors must act as one once JWST is in orbit.

We were shown a room with the tanks containing the completed mirrors, laid out on the floor in the same configuration they’ll be in the telescope itself:

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The watershed moment for JWST

By Phil Plait | September 13, 2011 6:30 am

[I want to start off this article with the conclusion, because the post is somewhat long and I want to avoid at least some of the slings and arrows that will inevitably turn up in the comments. Bottom line: I don't want to see JWST canceled, but neither do I want it to hurt other NASA missions. However, the reality of the situation is that unless Congress fully and independently funds JWST, it is very likely it will siphon funds from other missions and could do a lot of damage to them. Both the people supporting and attacking JWST make excellent points, but they also assume that extra money will not be found to fund it. I cannot say if that's a good assumption or not, but if it turns out to be true, JWST and NASA are in for an extremely distressing future.]

The James Webb Space Telescope, successor to Hubble, may be reaching the most critical juncture in its life: a vote by a U. S. Senate subcommittee on whether to fund it or not. The House version of the funding bill has the budget for JWST zeroed out. In other words, the House wants to kill it. The Senate has to vote on their version of the budget, and then the two chambers must reconcile the two versions. If the Senate votes to defund JWST, it’s essentially dead. The first version of that process may begin today.

What’s at stake

Here’s the thing: I don’t know how I feel about this.

On the one hand, JWST promises huge, huge science. Every time we’ve built a bigger telescope with new capabilities, we’ve learned things we didn’t even know we didn’t know. Hubble did that in spades, and JWST’s mirror will be far larger — and it will be the most sensitive telescope in the infrared ever built, allowing us to see deeper and more clearly in that wavelength range than ever before. It has and will provide new advances in technology and engineering, and will be a workhorse for science, used by hundreds of researchers for years to come. It will, quite literally, be the Hubble of its age.

On the other hand, cost overruns and mismanagement have been really bad (at the blog Starts With A Bang!, Ethan Siegel argues that this is both NASA’s fault and that of Congress, and I’m inclined to agree). A month or two ago I would’ve argued that this, though, was all behind us, and the cost to launch JWST would be small compared to canceling it. In fact, I did argue exactly this. However, things have changed. As I pointed out recently, an independent committee put together by Senator Barbara Mikluski found that the actual cost to launch JWST and run it for five years adds several billion dollars to the NASA estimate. Again, Ethan Siegel’s post describes this is all-too-painful detail, and the L. A. Times has an OpEd on this as well.

The impact of funding JWST

And there’s the heart of the issue. Read More

CATEGORIZED UNDER: NASA, Piece of mind, Politics, Science

Hubble's successor: doomed or saved?

By Phil Plait | August 23, 2011 10:17 am

The James Webb Space Telescope is planned to be the successor to the Hubble Space Telescope. It will have a 6.5 meter (21 foot) mirror (Hubble’s is 2.4 meters, or 8 feet), and will look at the Universe in the near- to mid-infrared, where cooler objects like planets, dust clouds, and ancient galaxies glow brightly.

Its fate also hangs by a thread.

Originally planned to cost under a billion dollars and already be launched by now — NASA has currently spent about $3.5B on the mission with a launch date no sooner than 2018 — delays and cost overruns have hit the project hard, prompting the US House of Representatives to axe the budget for JWST, essentially killing the entire project in their proposed 2012 Federal budget. I wrote about this when the news broke, basically saying this was a dumb idea. The JWST cost overruns have been widely claimed to be from administrative mismanagement. Even if true, as Julianne Dalcanton at Cosmic Variance has eloquently argued, those errors are behind us. The components of the telescope are mostly built, being tested now, and it would make more sense to spend the money it’ll take to assemble and launch the ‘scope than to cancel the project and throw away the investment already made.

Now two bits of news have come up which confuse the issue.

One is that, according to Aviation Week, a cost analysis ordered by Senator Barbara Mikulski (D-MD) shows that the current price tag of the telescope will actually be $8.7 billion, an increase of more than $3B over an earlier NASA estimate.

Ouch. Bluntly put, that’s a huge blow to any campaign to save the telescope, and will make convincing this current Congress to fund the mission once again much, much harder.

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CATEGORIZED UNDER: Astronomy, NASA, Piece of mind, Space, Top Post

Congress threatens America's future in space

By Phil Plait | July 14, 2011 6:30 am

One of the most aggravating things about having a representative government is dealing with the consequences of the choices they make.

We don’t get a direct vote on how money is spent, but we vote for the people who do. And sometimes they don’t make the best choices. Shocking I know, but just how bad these choices can be sometimes doesn’t hit home until those consequences come home to roost.

In a week, one of those choices is literally coming home: on July 21st, Atlantis will land for the last time, and the choices made for us over the past few years mean that we have no rocket system to take its place.

I’ll iterate once again that the Shuttle was canceled by Bush, and the followup rocket system, Constellation, was canceled by Obama when it was clearly over budget and behind schedule, and given the circumstances it was also very unclear it would perform as promised. I think both these decisions were correct.

Right now, the House of Representatives is making decisions about the future of NASA, and it’s looking like a 9% cut is in the works. That’s not written in stone; the Senate has to put together their version of the budget and then work with the House on compromises. That’ll be fun, given the Democratic-controlled Senate and the Republican House.

In the meantime, the House subcommittee in charge of NASA’s funds recommended totally cutting the budget for Hubble’s successor, the James Webb Space Telescope. The House committee above them approved it on Wednesday. So that decision to axe JWST will go into the House budget bill.


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CATEGORIZED UNDER: NASA, Piece of mind, Politics, Top Post

Congress puts NASA and JWST on the chopping block

By Phil Plait | July 7, 2011 6:00 am

When I saw the Presidential Budget Request this year for NASA, I was heartened: lots of money for commercial space transport and science. Obama hasn’t been a vocal supporter of NASA, so it was a relief.

Congress has countered, however. The House just released its Appropriations bill that covers science funding for NSF, NASA, NOAA, and NIST. Almost across the board: cuts. Massive ones.

This bill (PDF) actually keeps NSF at the fiscal year ’11 funding, although that’s $900 million less than the Presidential request. NOAA is being cut $100 million (2.2%), or $1 billion less than requested. NIST: cut by $50 million over FY11 (6.5%), $300 million less than requested.

But NASA is the one where the cuts are nothing short of savage. The cuts total $1.64 billion from last year, which is nearly $2 billion less than requested. That’s a cut of 8.8%. A billion of that is due to the Shuttle retiring, but the galling part is that the House is requiring that all funding for the James Webb Space Telescope, Hubble’s successor, be cut entirely. In other words, they are canceling the JWST program.

To be fair, the JWST project has been over budget, behind schedule, and mismanaged for years. It’s sapped money away from other projects as well. But the reason this is so aggravating is that despite all that the pieces are built and currently being assembled. I’m not sure it’s cost-effective to cancel it at this point; better to put a hold on it, audit the whole thing top to bottom, and re-organize as needed.

JWST has been a real problem, but it will also be one of the most spectacular observatories ever built. A six meter mirror in space tuned for infra-red observations, it will see farther and in more detail than any space telescope ever built. It will see galaxies when they were first forming, it will image planets orbiting distant suns, and will map our Universe like never before.

At this point, canceling it means billions of dollars will be thrown away, when the cost to complete it is far less*.

Since this is a House budget bill, I called my Representative, Jared Polis, and left him a message. I also tweeted him:

A little while later, he replied:

How cool is that? So I thanked him:

… and I retweeted his tweet. I noticed a while later several of my followers had tweeted their Reps, too. I don’t recommend communicating with your own Congresscritter only this way; emailing or a phone call in addition is better. If you feel strongly about this, please contact him or her.

As I understand it, the bill will get out of the subcommittee today and probably go to the full Appropriations Committee next Wednesday. The Senate will create its own version, and then the two bills will have to be reconciled before going to the President to sign. Canceling JWST may just be saber-rattling, but either way contacting your Rep is a good idea. We have a long way to go here; this is just the opening salvo.

Other people have written about this as well, including:

Julianne at Cosmic Variance
Risa at Cosmic Variance
Amanda Bauer
The e-astronomer
Sean Carroll at Cosmic Variance
Sarah Askew
Space News
The New York Times

Read those sites to get more info. And stay tuned; if this goes to vote I’ll have more info as it comes in.

* The JWST situation is similar to the Constellation rocket program which was also over budget and behind schedule. In that case, I supported the cancellation because it was still early enough in the project to actually save money, and it was unclear the rocket would work as promised. JWST is almost done, and is expected to surpass Hubble in many ways.

Hubble versus Webb

By Phil Plait | June 15, 2010 2:24 pm

Hubble is an awesome ‘scope, but its life is limited. Heavy and huge, there’s no way to bring it back, and with the Shuttle retiring there’s no easy way to get to it. Eventually its gyros will fail, it won’t be able to be pointed, and then that’s that.

For the past few years, NASA has been working on the James Webb Space Telescope, what some people call Hubble’s "replacement", which is a misnomer: it’s actually Hubble’s successor. It will do amazing astronomy too, but it has different capabilities than its predecessor.

How different, you ask? I’m glad you did, and so is NASA: they’ve put together a side-by-side comparison of the two observatories (warning huge Flash animation stuff).

Just how different are they? Check out the comparison of their mirrors:


Hmmm, the woman in the diagram is pretty tall, 1.8 meters — 6 feet! Of course, she’s in heels. But should she really have her hand on that priceless (if incorrectly ground) mirror?

Anyway, check out the comparison. I’ll miss Hubble when it goes, but I’m very excited about what JWST will do for astronomy, for science, and for humanity’s search for understanding. It will be a powerful, powerful tool.

CATEGORIZED UNDER: Astronomy, Cool stuff, NASA

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