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Thread: Space Telescope: The Next Generation (James Webb)

  1. #61
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    "...Preliminary tests have been carried out on instruments for the James Webb telescope inside the Blackford Hill facility's new £4 million extension..."
    http://news.scotsman.com/scotland.cfm?id=250242005

  2. #62
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    JWST has $1 billion cost overrun, may need to be scaled back

    The article is here for those of you with subscriptions to Science.

    Faced with a $1 billion cost overrun, NASA
    managers last week began to search for
    cheaper designs for the $3.5 billion James
    Webb Space Telescope (JWST). But
    astronomers say the initial attempt to scale
    back the complexity of the spacecraft and its
    instruments is a nonstarter for the mission
    slated for a 2011 launch as a follow-on to the
    Hubble Space Telescope.
    To summarize:
    - Northrop Grumman projects construction to cost $309 million more than expected.
    - Design changes have added $100 million.
    - Launching on the Ariane is going to cost more than expected.
    - New NASA accounting rules add another $100 million.

    Astronomers say scaling back (like reducing the mirror's size from 6.5 meters to 4) would make the whole mission pointless.
    Everything I need to know I learned through Googling.

  3. #63
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    Re: JWST has $1 billion cost overrun, may need to be scaled

    Quote Originally Posted by ToSeek
    New NASA accounting rules add another $100 million.
    How does that work?

  4. #64
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    Re: JWST has $1 billion cost overrun, may need to be scaled

    Quote Originally Posted by papageno
    Quote Originally Posted by ToSeek
    New NASA accounting rules add another $100 million.
    How does that work?
    "New rules that require NASA projects
    to include all costs associated with the
    program mean another $100 million."
    Everything I need to know I learned through Googling.

  5. #65
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    Re: JWST has $1 billion cost overrun, may need to be scaled

    Quote Originally Posted by papageno
    Quote Originally Posted by ToSeek
    New NASA accounting rules add another $100 million.
    How does that work?
    One factor is that, since the JWST project's inception, NASA has moved to full-cost accounting. Among other things of which I'm probably blissfully unaware, this means that certain support services formally taken out of the agency's operating budget at the top are now charged individually to each program. A prime example is use of the Deep-Space Network dishes, which is now charged to the program using it. The effect is supposed to be more transparent costs, with services such as the DSN being paid for by (at least on paper) transfers from users. This ought to be budget-neutral if done right, but in this case, it seems the cost cap didn't change with the new accounting rules. Ths may also affect costs for time of NASA personnel temporarily assigned to the project

  6. #66
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    Interesting timing. I just got an email about the ESA's mission Herschel, which, except for the primary mirror size, sounds a lot like JWST (and has an easier to pronounce name).

  7. #67
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    Quote Originally Posted by The Bad Astronomer
    Interesting timing. I just got an email about the ESA's mission Herschel, which, except for the primary mirror size, sounds a lot like JWST (and has an easier to pronounce name).
    And why couldn't NASA and ESA work together to make one?

  8. #68
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    Quote Originally Posted by Jorge
    Quote Originally Posted by The Bad Astronomer
    Interesting timing. I just got an email about the ESA's mission Herschel, which, except for the primary mirror size, sounds a lot like JWST (and has an easier to pronounce name).
    And why couldn't NASA and ESA work together to make one?
    Ditto:P. While I would like to see two of them up and running, I'd rather have 1 decent well funded effort than 2 missions that fail because someone didn't bother converting inches to cm, or because they can't grind a mirror to the correct specifications.

  9. #69
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    Quote Originally Posted by Jorge
    Quote Originally Posted by The Bad Astronomer
    Interesting timing. I just got an email about the ESA's mission Herschel, which, except for the primary mirror size, sounds a lot like JWST (and has an easier to pronounce name).
    And why couldn't NASA and ESA work together to make one?
    Hint: you may be unaware that ESA is a partner in JWST at a level 15% or more. In fact, their contribution includes launching the instrument on an Ariane V.

  10. #70
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    Great so not only is JWST not a replacement for Hubble, it might not be anything!

    CJSF
    "Flipping this one final switch I'm effectively ensuring that I will be
    Overcoming all resistance long after my remains have been
    Vaporized with extreme prejudice and shot into outer space.

    I'll be haunting you."

    -They Might Be Giants, "I'll Be Haunting You"


    lonelybirder.org

  11. #71
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    Quote Originally Posted by Christopher Ferro
    Great so not only is JWST not a replacement for Hubble, it might not be anything!

    CJSF
    Perhaps it isn't a coincidence that the JWST cost overrun closely matches the Hubble repair mission cost. Perhaps I'm paranoid. 8-[

  12. #72
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    Webb needs to be axed.

  13. #73
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    Quote Originally Posted by publiusr
    Webb needs to be axed.
    The National Academy of Sciences has JWST first on its wish list of new astronomical observatories. I'd be interested in knowing your rationale for cancelling it.
    Everything I need to know I learned through Googling.

  14. #74
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    To start with--we already have Hubble--and Webb is not a true optical replacement that many want.

    Secondly--once Webb is put up there--there will be no way at all to service it--even though it isn't that far away (farther than Hubble--and out of easy reach of CEV).

    Thirdly--money from this and other cuts will go into rocketry--which has been neglected. http://www.spacedaily.com/news/launchers-05zw.html

    Lastly: You all know of my interest in HLLVs. Here is one reason I support them:

    http://www.tsgc.utexas.edu/archive/design/foci/ Now that's a space telescope NO planetbound scope will match.

    The infrastructure we need for truly grand missions will be undermined if every Mars rover and every 'scope is given money--money that will be wasted launching these things on EELVs--which can only eat into VSE as envisioned by Griffin.

    The robotics types view VSE as a waste and a distraction--but they forget that without human-rated boosters like R-7--we wouldn't even have GOES weathersats up there. The military only wanted TOPOL-M/Minutemen sized missiles no good for anything else.

    My point is that we have focused too much on payloads--and not enough on vehicles. The pointy heads and white coats might not like Griffin now--but if they would support him instead of undermining him with every little wish list--the HLLV he supports (with zeal equal to mine) will allow for truly grand probes they can hardly imagine.

    But this is what happens when scientists dis engineers and their needs--constantly putting off the folks who give them the rockets--without which there is no space exploration.

    Horse first--cart later. That is Griffin's take--and I agree with him.

  15. #75
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    Quote Originally Posted by publiusr
    To start with--we already have Hubble--and Webb is not a true optical replacement that many want.
    Webb focuses on the infrared because that's what's of greatest interest to astronomers. Visible astronomy can be done from the ground; infrared can't.

    Secondly--once Webb is put up there--there will be no way at all to service it--even though it isn't that far away (farther than Hubble--and out of easy reach of CEV).
    Servicing is overrated (so long as you get it right the first time!). A replacement Hubble could have been launched for the cost of the servicing missions.

    Thirdly--money from this and other cuts will go into rocketry--which has been neglected. http://www.spacedaily.com/news/launchers-05zw.html
    I won't argue with you here. It seems like everything we've got now is basically a Delta or an Atlas - 40-year-old technology.

    Lastly: You all know of my interest in HLLVs. Here is one reason I support them:

    http://www.tsgc.utexas.edu/archive/design/foci/ Now that's a space telescope NO planetbound scope will match.
    That would be pretty cool. I also have a sneaking fondness for the TAU mission.

    The infrastructure we need for truly grand missions will be undermined if every Mars rover and every 'scope is given money--money that will be wasted launching these things on EELVs--which can only eat into VSE as envisioned by Griffin.
    People see a limited pot and want their share. With NASA's limited budget, it's hard to blame them.

    The robotics types view VSE as a waste and a distraction--but they forget that without human-rated boosters like R-7--we wouldn't even have GOES weathersats up there. The military only wanted TOPOL-M/Minutemen sized missiles no good for anything else.
    That seems arguable. There's no way of telling what might have happened if manned spaceflight had gone differently.

    My point is that we have focused too much on payloads--and not enough on vehicles. The pointy heads and white coats might not like Griffin now--but if they would support him instead of undermining him with every little wish list--the HLLV he supports (with zeal equal to mine) will allow for truly grand probes they can hardly imagine.
    But on a limited budget, how can you afford both the rocket technology and the "grand" probes?

    But this is what happens when scientists dis engineers and their needs--constantly putting off the folks who give them the rockets--without which there is no space exploration.

    Horse first--cart later. That is Griffin's take--and I agree with him.
    But the cart is the reason for the horse. There's no point in developing rockets for their own sake (though that's just about what was done with the space shuttle, it seems).
    Everything I need to know I learned through Googling.

  16. #76
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    Once the big rockets are done--then the money goes on the probes. The money was spent on the Thor IRBM before it could become the Delta--now its paid for and has been around so long it has become a crutch.

    Imagine if all 100 or so Shuttle flights had been HLLV stacks without the orbiter. (with Energiya Buran it would have been a mix)

    Can you imagine what we would have had up there had the orbiter not been required as part of the stack because it had the three SSMEs and not the ET?

    100 missions with 100 tons lofted each time. Do the math.

    Now that would be a space program we could all support. It's not too late--if Griffin has his way.

  17. #77
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    JWST squeezed

    Here's a new scientist story about cost overruns with the James Webb Space Telescope:
    http://www.newscientist.com/article.ns?id=dn7423

    They are looking at ways to reduce the overall cost of the mission, but are unwilling to launch on a cheaper Ariane 5, as opposed to a Boeing Delta IV.
    Forming opinions as we speak

  18. #78
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    Most people directly or indirectly responsible for that state of affairs - costing skyrocketing and making it easier to give up space missions - would find it natural when it comes to their own part, even if they see that it is deplorable on the whole, which many would not concern themselves with. If more than a handful saw the necessity of progress and agreed with the need of at least postponing if not giivng up some of one's own immediate pleasures and so on, humanity would progress far more dynamically.

  19. #79
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    arXiv today has a paper on the design and uses of JWST here, titled How JWST can measure First Light,
    Reionization and Galaxy Assembly.


    Many parts are over my head, but much is accessible. One conclusion is
    In conclusion, if the JWST is to remain NASA’s First Light machine, it needs
    to have a 6.5 m class aperture and its near-IR to mid-IR capabilities to assure
    proper measurement of the expected First Light objects.

  20. #80
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    The telescope that will replace Hubble..?

    Please anyone.


    Were can I find a good link..?

  21. #81
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  22. #82
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    Worthy in its own right as a different window on the universe, JWST won't 'replace' Hubble's visible spectrum capabilities but will compliment the research done by 'seeing' into the IR.

  23. #83
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    Quote Originally Posted by frogesque
    Worthy in its own right as a different window on the universe, JWST won't 'replace' Hubble's visible spectrum capabilities but will compliment the research done by 'seeing' into the IR.
    Yes, in that sense Hubble doesn't have any successor, which is very bad thing. Hubble is also an UV telescope, and no Earth-based telescope can replace it.

    JWST is Hubble's successor in the sense that it is the next large NASA/ESA telescope project. Otherwise it is more like Spitzer's successor.

  24. #84
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    If they pump out pretty pictures, the general public won't be able to tell the difference. For as much great science as HST has done, let's face it: It's a cultural icon because it shows people that the universe is beautiful. Far too many people think that any pretty picture of the sky is the result of Hubble now, in sort of the same way that they just assume that any funny song is the product of "Weird Al" Yancovic (even 10 years after the peak of his career).

  25. #85
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    Thx guys

  26. #86
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    You mean other people write funny songs other than Weird Al?

  27. #87
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    Quote Originally Posted by gopher65
    You mean other people write funny songs other than Weird Al?
    Ray Stevens was the guy that Weird learned from. Ray's been writin' the funny stuff since I was a kid. (loooooooooooooooooong time ago)

  28. #88
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    Quote Originally Posted by Kristophe
    If they pump out pretty pictures, the general public won't be able to tell the difference.
    That may be the bad news. JWST is unlikely to deliver sharper images than HST in the deep-red overlap region, blurrier due to diffraction at longer wavelengths, and doesn't have a camera with pixel count remotely approaching ACS. On top of that, most astrophysical objects show less detailed structure in the IR because of we don't see dust clouds as distinctly. (Exception: some nebulae have quite interesting structure to be seen in some near-IR emission lines, uncovered very well by even ground-based IR imaging.) So I worry a bit about the PR impact because JWST images won't look any better than HST's - the new impact will be in the science, for which you have to read the caption which can get garbled anyway.

  29. #89
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    The resolution does seem to be no better, in general, than the Hubble - both rated at .1 arc-sec. JWST proposed specs.... here .

    The Spitzer might be a reasonable PR comparison. Would you say the Spitzer has mostly augmented Hubble's attention-getting work from the public's perspective? [If so, this, of course, is unfair to the great work Spitzer has really accomplished.] The JWST will be in addition to the Spitzer, so it might get even less recognition.

    However, wouldn't the adventures into accretion disks and planetary discoveries around dwarfs be a real plus? Yet these will not be very colorful or detailed due to their size and distance.
    We know time flies, we just can't see its wings.

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