Astronomical Engines

A Look at the James Webb Space Telescope

An artist's rendering of the JWST

Good morning again, everyone.

It still is the morning, correct? My coffee is still hot and [opens curtains] it’s quite bright out. Morning it is.

Today we’re going to look at the New Technology Space Telescope, now known as the James Webb Space Telescope. As I’m sure you all know, James Webb was the second administrator of NASA, and evidently did some good things as a bureaucrat during his reign there. It looks to be an ill-omened name, however, considering all of the bureaucratic bungling and huge cost overruns that the project has had, and is still having. The project was originally estimated to cost $1.6 billion, but as development progressed, that grew to $5 billion by the time that construction was confirmed and scheduled to start in 2008, with a launch date of 2011. Because of the cost overruns, NASA shuffled the management, but that caused a big delay in the planned launch date, which was now pushed back to 2018 at least, and maybe out to 2020. Maybe longer. And the cost keeps going up. In July 2011, the cost had risen to $6.5 billion, and in August it rose to 8.7 billion for the cost of the telescope and 5 years of operation.

Eight point seven billion dollars. Jeebus H. Fooking Kleist on a ladder.

Ahem.

All of you should know by now that I’m an astronomy enthusiast, and I absolutely love the great big telescopes, but I’m starting to question whether this one is worth it or not. That’s one helluva lot of money for one telescope, and it’s sucking away money from other worthy programs.  And of course, there are political machinations going on in Congress, but I won’t get into that.

Anyway, I am troubled by the project.

I does have some interesting technology going into it, which is what I actually wanted to talk about. The JWST is the replacement for the Hubble Space Telescope, but rather than being in Earth orbit, it will be placed in orbit around the L2 Lagrange point. The JWST also has a much bigger mirror than the Hubble, 6.5 meters in diameter, with 5 times the collecting area. The mirror is a segmented type, and is made of gold-coated beryllium segments rather than glass, which has about one tenth the mass of a glass mirror of the same size. The segmented construction allows the mirror to be folded up so that it can fit into the rocket, and then unfold after launch. I hope it unfolds better than the main antenna on the Galileo probe did. Ahem.

Comparison with Hubble primary mirror.

The JWST is designed to work in the longer wavelengths of the visible spectrum and the near-infrared due to its mission. It will look deep into the sky to search for events happening right after the big bang, study the formation and evolution of galaxies, the formation of stars and planetary systems, and the study of planetary systems. It has all sorts of nifty instruments on board for the missions, but I won’t bore you with them at this time.

A beryllium mirror segment coated with gold

One thing that I find troubling about the design of the JWST, is that it isn’t designed to be repaired or upgraded like the Hubble is. Astronauts will be able to go out and replace a solar panel, or jump up and down on the mirror to get it to unfold, but that’s about it. Considering how useful it turned out to be for the Hubble to be worked on, I think that it is a mistake to not have the same capability on the JWST. Especially when it costs 8.7 billion f**king dollars so far for a five year mission.

So there is my quick rundown on the James Webb Space Telescope. I like the idea of the telescope. I don’t like how much it is going to cost us. What do you guys think? Is the thing worth it?

 

References:

https://secure.wikimedia.org/wikipedia/en/wiki/James_Webb_Space_Telescope

http://www.jwst.nasa.gov/index.html

http://www.washingtonpost.com/national/health-science/budget-fight-rages-over-james-webb-space-telescope/2011/10/13/gIQALjYLKM_story.html

 

  • P161911

    NASA does seem to have a history of extending projects way beyond their design life, just look at the Mars rovers. So I wouldn't sweat the 5 year thing too much. It seems that most things NASA does either end in a big splat or last forever. Let's hope this one isn't a splat.

    • The Professor

      I'm hoping that all goes well too, and that it's a robust enough craft to be able to have its mission extended. The Russians aren't going to launch the thing are they? They just got done screwing up another Mars mission.

  • highmileage_v1

    I think you should go for it, not my tax dollars though so I don't have much of a say. As for Hubble-like maintenance, don't you need a Shuttle or similar?

    • mr. mzs zsm msz esq

      Also I think L2 is farther than the moon from the earth, yikes on repair missions during the operational life! I think the Professor wanted a replacement for the Hubble to be in a closer to the earth. I never knew about all the tape recorder and antenna problems with Galileo and the neat work arounds, are those NASA guys smart as rocket surgeons or what!

  • ademrudin

    As you note, the JWST is intended for the Sun-Earth L2 Lagrange Point, which is WELL beyond where human beings have ever flown. Considering the state of our manned space program, designing it for future maintenance would be… mildly silly, to say the least.

    I'm more concerned about the optics and instruments just hanging out there, rather than being shielded inside something, like on the Hubble. Aren't they worried about micro-meteoroid strikes, or something? I guess there's basically no human-made space junk at that altitude…

    • The Professor

      Good point, although we could fly out there if there was sufficient reason. We couldn't do it tomorrow, obviously, but a craft that could travel to L2 and back could be built with current tech.
      When the JWST was proposed and designed, the shuttle was still flying, but I suppose that its termination date had already been set. When was it decided when the shuttle program would be terminated? I'm too lazy to go looking right now.

  • So how do they make those mirror segments out of one of these?

    <img src="http://i.imgur.com/g2Ljb.jpg&quot; alt="" title="Hosted by imgur.com" width="500">

      • The Professor

        I just noticed this link and read the article there. Ye gods, what a pain in the neck to machine! I was aware of some of Be's properties, but I was unaware of how tricky it is to machine. A funny thing, I also use many of the techniques mentioned in the article when I'm doing certain types of joinery and fabrication with certain woods. Thanks for the link, I want to try to find out more about how the JWST mirrors were made.

        • You're welcome. My research group once needed to have a set of diamond-anvil cell seats made out of beryllium. Quite useful for its transparency with respect to conventional Cu Kα x-ray diffraction techniques, but surprisingly expensive to have produced, thanks mostly to its toxicity but also in no small part to its material shortcomings.

    • The Professor


      <img src="
      https://farm7.staticflickr.com/6092/6386212651_82565f5653_o.jpg&quot; width="400" border="2" style="border:2px solid black;" alt=" " />

      • Ahhh…always the right tool and the right artisan to wield it…

  • Number_Six

    It's like a rabid chimp and a meth-addicted lemur playing catch with a Faberge Egg…

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