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First victim of moon base/Mars mission?

  1. Jan 16, 2004 #1

    Njorl

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  3. Jan 16, 2004 #2

    LURCH

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    The decision to abandon Hubble was made some time ago. Nothing to do with the manned space program, it is because the tellescope has already outlived its projected lifespan, and its replacement is on the way, the James Web Space Tellescope, or JWST.

    Should be a great advance! But I must say, I don't agree with the plans to deorbit Hubble before JWST gets started. I agree that we should stop repairs, since they are getting way to expensive, bvut I think we should just let it remain orbital for now. Once the JWST is in orbit and functioning, then we can deorbit Hubble; it's niot going anywhere. And if something should go wrong with the Web (perish the thought, but accidents do happen), then we go do the repairs we left undone and continue to use the Hubble.
     
  4. Jan 16, 2004 #3

    selfAdjoint

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    Note that if the President's Mars iniative gets passed by Congress, there won't be any followon telescope. All the money for unmanned programs would be funnelled into the Mars thing.
     
  5. Jan 17, 2004 #4
    Perhaps the ending of Hubble had already been made but nontheless it would be disappointing to see it go.

    Would that mean that any possible mission to Pluto (the Pluto-Kuiper Express) would be shelved as well?
     
  6. Jan 17, 2004 #5

    Ivan Seeking

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    http://www.cbsnews.com/stories/2004/01/16/tech/main593826.shtml
     
  7. Jan 17, 2004 #6

    LURCH

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    The JWST has been cancelled? That would be a shame, I had not heard about that. Where did you hear it?
     
  8. Jan 17, 2004 #7
    Could Moon-based telescopes be more effective than Earth-orbit telescopes?
     
  9. Jan 18, 2004 #8
    I don't think so. It may be possible to build bigger telescopes on the moon, but the bigger they are the bigger the risk of being hit by meteors.
     
  10. Jan 18, 2004 #9
    Enourmously given the moons near absent atmosphere...the Earth's atmosphere is so dense that it causes objects in the viewfinders of telescopes to appear to be "twinkling", it's a bit like looking through the rising heat off of a desert floor...the Moon has none of that, very, VERY little atmosphere, much better for observation the Earth based...don't know just how comparable to 'space based' though...
     
  11. Jan 18, 2004 #10

    Nereid

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    The main advantage of placing a telescope in space is to detect EM that is absorbed by the atmosphere, from gammas to UV, then IR to microwave. In the NIR and FIR there is also the advantage of being able to cool the scope better, so making the job of accounting for the radiation from the scope itself easier.

    Better resolution is a good thing, but with the latest adaptive optics systems at the large Earth-bound observatories (including 'artificial stars'), space-based telescopes like Hubble may no longer be a cost-effective choice.
    I can't see how they could be; 'free space' is a better location in every respect.
    Although no one has said anything about changing budgets and plans for missions already underway or in the pipeline, the depressing history of manned spaceflight leads one almost inevitably to conclude, as SA says, that just about ALL other NASA missions will be cancelled - JWST, Pluto-Kuiper Express, even GLAST .

    [Edit: removed text more appropriate to Politics and World Affairs]
     
    Last edited: Jan 18, 2004
  12. Jan 18, 2004 #11

    selfAdjoint

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    The question was about Moon based telescopes vs. Earth-orbit telescopes like Hubble.

    I think that with a thoroughly developed human presence on the moon, very large telescopes (light gravity, stable underpinning) could be built on the side of the Moon opposite to the Earth ("Privolva" in Kepler's term). With no earthglow or reflected light to interfere, these telescopes would be better than anything we can build now, either on Earth or in orbit.

    I want to emphasize that we don't want to place a settlement on the far side of the Moon until the settlements on the near side are fully developed. They would have to support the astronomers, and communications around the Moons limb would be vital.
     
  13. Jan 18, 2004 #12

    marcus

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    Nereid, agree 100 percent
    stationing humans on moon a bad scientific investment strategy
    with potentially terrible consequences for the
    scientifically productive side of the space program

    why put telescopes down in the lunar well when they
    work so much better in orbit
    (including solar orbit like WMAP)
    and when it is so costly just to get down into, and back out of, the well.

    Six good points and a conclusion. Yes deeply cynical unless (what is worse) the advisors feel morally justified in trashing any and all Federal programs including space-based science if it can help maintain them in power, because they believe the sacred agenda (of dismantling government and making its body-parts into businesses run for-profit) transcends all other concerns whether of health care, environment, prosperity, international harmony, or science.

    Someone who is blindly self-righteous may not even know that he or she is acting cynically.
     
  14. Jan 18, 2004 #13
    Really good points, for "Politics and World Affairs"...wouldn't lunar based be easier to repair then space based?
     
  15. Jan 18, 2004 #14

    selfAdjoint

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    why put telescopes down in the lunar well when they
    work so much better in orbit
    (including solar orbit like WMAP)
    and when it is so costly just to get down into, and back out of, the well.


    The lunar gravity well is trivial. That long ago astronaut golf shot almost went into orbit. The reason given for the Hubble demise is that it costs a billion bucks a run to maintain it with the shuttle. Think over the economics a little more.
     
  16. Jan 18, 2004 #15

    Nereid

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    SelfAdjoint raises a good point about support etc; if there were good support on the Moon, then the economics may be more favourable.
     
  17. Jan 18, 2004 #16
    Here's a recent article on the subject of lunar astronomical observatories:

    Does the Lunar Surface Still Offer Value As a Site for Astronomical Observatories? by Daniel F. Lester, Harold W. Yorke, and John C. Mather

    Here's the abstract:

     
  18. Jan 18, 2004 #17
    If they (probes) could be "Made on the Moon" then the launching would be cheaper, if the fuel is available, as the gravity...
     
  19. Jan 19, 2004 #18

    Nereid

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    The infrastructure needed for 'Made in the Moon' probes would be considerable, and quite costly in terms of time and resources (fantasies like 'nanotech' aside). Like just about all manufacturing, it'd likely end up as a hybrid - some done on site, some shipped from the Earth; final assembly in space?
     
  20. Jan 19, 2004 #19
    Forgive me why would you assemble in space when you can assemble in a Low G environment where people can carry enormous weights around like toys?

    "Made on the Moon" simply requires the 'Keystone' trades for process assembly, materials should be local, energy source, small scale manufacturing is quite efficient, make atmosphere, make water, how difficult is it?
     
  21. Jan 19, 2004 #20

    Nereid

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    The last satellite 'factory' that I toured wasn't all that small, and it seemed to have an awful lot of specialist equipment (little or none of which was made on site). The components came from all over ... the world. IIRC, big astronomy and solar system probes have one contractor for the project management and assembly (under a science director?), but dozens of sub-contractors, including university labs for some of the specialist instruments.

    As any country which has toyed with autarky has found to its cost, self-sufficiency is very, very costly. So any Moon-based facility would still have a heavy reliance on Earth.

    If the costs of getting into Earth orbit can't be reduced by at least a factor of 100, economics would suggest that a Moon base would make the 'heavy' components of any probe/observatory, and get just the 'light' ones - such as software, design, detectors - from Earth.

    Space assembly may be attractive with good robots (humans are no good, even on the Earth); there's an awful lot of mechanical stress involved in launching an object, even from the Moon.
     
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