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Radio Telescopes on Moon to Study Cosmic Dark Ages

Posted by Soulskill on Thu Feb 21, 2008 06:09 PM
from the ye-olde-moone dept.
NASA Moon Space Science
The Narrative Fallacy brings news that NASA has awarded a $500,000 grant to develop plans for an array of radio telescopes to be located on the moon. The telescopes would be used to gather data from the earliest stars and galaxies, observations of which are difficult from Earth due to the ionosphere and terrestrial broadcasts. The grant was part of NASA's sponsoring of 19 "Next Generation Astronomy Missions." Quoting: "The Lunar Array for Radio Cosmology (LARC) project ... is planned as a huge array of hundreds of telescope modules designed to pick up very-low-frequency radio emissions. The array will cover an area of up to two square kilometers; the modules would be moved into place on the lunar surface by automated vehicles. The new lunar telescopes would add greatly to the capabilities of a low-frequency radio telescope array now under construction in Western Australia, one of the most radio-quiet areas on Earth."
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Submission: Radio Telescope on Moon to Study Cosmic Dark Ages by pickens (49171)
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  • Hrm. (Score:4, Funny)

    by KublaiKhan (522918) on Thursday February 21 2008, @06:13PM (#22509190) Homepage Journal
    Just a bit far to go on a LARC, ain't it?

    < /british >

  • Outstanding (Score:5, Interesting)

    by Protonk (599901) on Thursday February 21 2008, @06:14PM (#22509196) Homepage
    The moon makes for an excellent platform for automated telescopes. People are going to bring up the tired "appolo for diamonds" argument but it doesn't have any bearing on this. The moon has no atmosphere to speak of, little radio interference from the earth and ample room to set up a large array.

    This requires less investment than manned missions (which dictate a return and have a HUGE space/safety cost). It will allow us to see other things than what is suggested in the grant--Changra, hubble and the like all have been used for things that were not conceived of during the design phase.

    • Once we start putting radio telescopes, human colonies, and massive solar arrays up there, that little rock is going to be covered pretty fast.
      • Not really. 3.793 × 10^7 sq. km is a lot of space. And if it is covered, so what? All the better.

      • Re:Outstanding (Score:5, Funny)

        by fred fleenblat (463628) on Thursday February 21 2008, @06:37PM (#22509426) Homepage
        (a) the cost of transit to/from the moon per pound is so high that only the lightest, skinniest people like paris hilton will be allowed in space. in fact they should be required to be sent into space.

        (b) the moon has no oceans, therefore 100% of land area is available for condominiums, hotels, highrises, and shopping districts. Unlike the earth which of which only 20% or so is habitable land. Ideally we would launch the most habitable parts, like Washington DC, to the moon in their entirety to take full advantage of the economy of scale, then convert what was underneath Washington DC into higher value land, like a swamp.

        (c) as you could see from last wednesdays lunar eclipse, the educational value of viewing the lunar eclipse from the moon would have been greater than viewing it from earth. No child left behind and all that.

        What was the question?

    • Re:Outstanding (Score:4, Informative)

      by fred fleenblat (463628) on Thursday February 21 2008, @06:19PM (#22509254) Homepage
      >> little radio interference from the earth

      Further, I suspect if you set it up on the far side of the moon, you'll get zero interference from earth at all. Maybe some 60 hz hum...but kilohertz and above should be clean.
      • right. It is just easier to say "very little" than it is to say "none" and have to explain that I mean "practically none".
      • But that's where the alien moon base is...
        • Not true! The only thing there is a "sound"stage where the aliens faked their Earth landing.
          • Under the terms of the Galactic Confederacy, all these worlds are ours except Europa. Attempt no landing there.
      • Only yesterday, they were proposing to send some telecommunications satellites to orbit the Moon so that there would be all-over lunar coverage for astronauts with satellite phones.

    • Re: (Score:3, Interesting)

      by Dr. Eggman (932300)
      Alright, but what happens when something breaks down? With no atmosphere to burn them up, smaller space debris may impact the surface near the telescope (and stirring up the soil) or the device itself. We already have hear of that the extremly abrasive qualities of the lunar soil. That soil that will find its way into the telescope (especially bad for any moving parts.)

      I too, however, am optimistic. Not so much about what the telescope will grant us, but rather the challenges to material science. Solution

      • We already have hear of that the extremly abrasive qualities of the lunar soil. That soil that will find its way into the telescope (especially bad for any moving parts.)

        Too bad we don't know how to design and build phased-array radars... oh, wait.

      • Re:Outstanding (Score:5, Interesting)

        by CodeBuster (516420) on Thursday February 21 2008, @07:22PM (#22509800)

        We already have hear of that the extremly abrasive qualities of the lunar soil. That soil that will find its way into the telescope (especially bad for any moving parts.)
        I was going to mention the exact problem and it does has the potential to be a problem because, as you mention, lunar dust is extremely abbrasive and fine (imagine sub micron rock particulate with razor sharp and hooked edges because it has never been eroded by wind or water) so it tends to damage or compromise any softer materials that it comes into contact with. However, upon further reflection I believe that the problem, in this case, would be manageable for the following reasons:

        (a) The telescopes and related equipment, or at least the parts directly in conctact with the lunar surface, will not be moving around after touchdown so the amount of dust that gets disturbed should be minimal and landing air bags (ala the mars missions) should help shield any sensitive parts during the landing cycle. the parts that do move will not disturb the dust because they will not be in direct contact with the lunar surface AND there are no air currents or other atmospheric effects on the moon to whip up dust from parts moving around (even if they are only millimeters above average surface elevation) which are not in direct contact with the lunar surface.

        (b) radio telescopes can be made out of metals and durable plastics without the need for sensitive optics such as finely ground glass lenses so the danger from abbrasive lunar dust could be minimized in this regard by judicious use of durable and hardened parts.

        The micrometeorites are a more serious issue. There have been subsequent pictures taken by probes of known Apollo landing sites which reveal new small craters (i.e. craters which occurred near the landing sites in between the time when the probes took the pictures and when the Apollo astronauts left the moon on the ascent stages of their landing vehicles). It is possible that many smaller meteorites have struck the Apollo lander descent stages that were left behind on the moon (although nobody can be sure because they are too small to resolve individually on the lunar surface by telescope and nobody has gone back since to check on their condition). However, even with this potential problem the radio telescope offers an interesting solution.

        The individual telescope elements of the radio telescope are less important than the network of them which makes up the whole. This why radio telescopes on earth, such as the very long baseline array [wikipedia.org], with stations on different continents aggregated together into a single "picture", are distributed rather then building one VERY large singular dish (i.e. one half the size of earth). The individual telescope elements on the moon could be replaced with new ones as needed if individual units, for whatever reason, become non-operable.
      • Radio telescopes receive other wavelengths that are at least as interesting to astronomers and astrophysicists as optical telescopes.

        And--if you'd bothered to read the article--the effectiveness of Earth-bound radio telescopes is limited by the RF properties of the ionosphere and the background noise from Earth-bound radio broadcasts.

      • Re: (Score:3, Interesting)

        by Protonk (599901)
        How does a payment of 500,000 dollars for a researh grant to send unmanned radio telescopes to the moon in order to study something obscure generate a bigger budget?

        Do you just let stuff spill out of your ears when you make comments on this sort of stuff?

        First, the array would be bigger than Arecibo, which is already smaller (by virtue of not being an array) than others on earth right now. The limit to accuracy for those arrays is RF interference and the ionosphere.

        Second, NASA is ALWAYS short money and lo
          • ?? Alpha male?

            I mean, 500k is a fair amount of money to spend on PR (Far, FAR less than the 2b we spend on recruiting/bonuses for the american military), but my point was that it wasn't spend on PR. I just wasn't. It is beyond disingenuous to claim that this is a PR stunt. It is a research grant. Spending it on PR would be something like this:

            "NASA spent 500,000 dollars today to secure the passage of three adult entertainment stars on the space shuttle today, hoping to determine the impact of space on

      • Re:Outstanding (Score:4, Interesting)

        by Protonk (599901) on Thursday February 21 2008, @07:04PM (#22509656) Homepage
        It's apollo. My ability to spell....sucks. Basically, if you took the cost per pound of payload for the apollo moon missions you would come to the conclusion that even if the surface of the moon were made of pure diamond and it was easily mined (read: pick it up off the ground), it would not be worth the trip. There are a number of fallacies invoked when people use it to describe current space travel, but the basic principle (that $/lb of payload is very high) stands.
  • everyone knows they are just going to use the telescope to watch the Amazon women change clothes.
    • And there's a problem with that?

      I wonder, what did you find buggy about the OS-X server?
      Just curious, I never used it myself.
    • that must have been what that one they shot down was for
      • Does it _always_ face the earth 100%, or does the moon have a precession?

        I can't seem to find any info on this...

        • Re:Yeah right (Score:5, Informative)

          by Deadstick (535032) on Thursday February 21 2008, @07:33PM (#22509920)
          The moon's orbit is not perfectly circular, and its axis of rotation is not quite perpendicular to the plane of the orbit. Those effects combine to produce an apparent rocking motion, on a time scale of weeks, called libration. Thanks to that, we can see almost 60 percent of the moon's surface at one time or another.

          rj

  • Welfare for engineers (Score:3, Insightful)

    by Grandiloquence (1180099) on Thursday February 21 2008, @07:06PM (#22509680)
    Like most of NASA's programs, this basically amounts to a jobs program for scientists/engineers. Notice that the funding is for the plans for an array of telescopes, not for the actual construction of said array. Building an array of telescopes on the Moon would likely require astronauts to spend months on the Moon, even if most of the telescopes came pre-assembled. Without any infrastructure on the Moon to support those astronauts, building an array of telescopes there is a pipe dream, and will remain so for the foreseeable future.

    If any plans end up being actually produced, they'll likely be filed away in a drawer and forgotten. Pessimistic? Sure. But, that's the way NASA has worked for decades now.

  • The Standard Objection Applies.. (Score:3, Interesting)

    by QuantumG (50515) <qg@biodome.org> on Thursday February 21 2008, @07:06PM (#22509684) Homepage Journal
    Why not just put the telescopes in a geostationary orbit around the Moon so they are always on the dark side and therefore shielded from the Earth? Soft landing telescopes of any significant size is hard work. The only reason lunar telescopes makes more sense than space telescopes in lunar orbit is if you build the lunar telescopes from lunar materials... and we're not anywhere near that capability yet.

    • interesting. you'd get a cleaner signal but there would be other obsticals.

      wouldn't you need some form of communications system im place to route the signals?

      possible a satellite in a lunar polar orbit?

    • Re:The Standard Objection Applies.. (Score:5, Interesting)

      by Fëanáro (130986) on Thursday February 21 2008, @07:29PM (#22509892)
      There are no geostationary orbits that stay behind the moon. But we could maybe put a satellite in a Lissajous orbit around the lagrange point [wikipedia.org] L2 behind the moon.

      To send signals back you would need a relay satelite thougth

      • Re:The Standard Objection Applies.. (Score:4, Insightful)

        by Steneub (1070216) on Thursday February 21 2008, @08:20PM (#22510316)
        Logged in to post exactly this. Putting a telescope in a lagrange point solves the problem of not being able to directly communicate with it due to it being on the other side of the moon. Another advantage of direct communication is getting visual confirmation of any movements or adjustments made. Sensors are great, but I don't care how good the tech is - something will always go wrong that you didn't think of.
    • Because there is no stable geo-synchronous orbits around the Moon?

      Also, for the wavelengths they are looking at, you need something that is kilometers wide and able to be effectively controlled.

      They are not talking about some telescope with a mirror and camera. This is closer to a huge array of dish antennas that are linked together and point in a given direction. They actual dish can be fairly small and moved about to change the size of the baseline.

    • I would not build them on earth and transport. I would simply build them out of the material on the moon. It really is the only way. Far cheaper and it will leave an infrastructure in place to build other things.
    • You could make a lunar telescope array far, far larger than anything you could park at the Earth-Moon L2.

      • But we won't.

        • If done in the right way, this could be used to build infrastructure on the moon. It seems to me, that if we BUILD a radio telescope on the moon, then the same machinery used to build that will go into building other structures such as a regular scope. In addition, if this is outsourced to somebody like bigelow, they will use that as a means of constructing a lunar base.
  • are also being funded. Follow the last link [nasa.gov]

    I particularly like the idea

    Imaging nearby Earth-sized worlds using large telescopes with multiple instruments and separate spacecraft to block the light from these exoplanets' host star (Webster Cash, University of Colorado, Boulder; David Spergel, Princeton University, N.J.).

    This seems very cool - the idea is that you put a big screen out in space to block the light of the host star, but not that of the star's planet. This is not a new idea - the problem is diffraction around the screen (occulter). But it looks like Cash and Spergel have found a design that minimizes the diffraction.

  • NASA can't even afford to keep flying the shuttle, and they want to put a radio telescope on the moon? I guess they're allowed to dream.

    • Re: (Score:3, Informative)

      by usul294 (1163169)
      The moon goes around the Earth, one face always faces the Earth. Over the course of 28 days the dark side of the moon will see the entire sky with a giant ball of rock in between the observatory and Earth

      • Re:As I understand it (Score:5, Insightful)

        by rijrunner (263757) on Thursday February 21 2008, @07:27PM (#22509856)
        Well, not quite.

        This type of observatory requires a lot of smaller units that add up to a total resolution of the receiving surface. The best resolution is directly overhead of the site. As you try to observe items that are low on the horizon, you lose a great deal of the quality of the observation as the effective size of the array is diminished.

        For example:

                                **** (what you are observing)

                                ^^^^ (The array).

        The array is effectively as wide as its deployment diameter.

        Now, suppose you are observing from a couple other angles:

                                          ****

                                ^^^^

        From that angle, the array is apparently smaller. You can angle them to make sure you have the same strength, but you have to increase the size of the array as a direct function of the observation angle to give equivalent baselines for the observation.

        So, yes, you can see in any direction around the Moon, but placement on the Moon is not a simple matter.

        Consider that you don't want it pointing towards the sun either. Or, maybe you do. That's an interesting argument right there. You'll get data from the sun, but you'll also have periods where you have nothing *but* data from the sun. Similarly, Jupiter kicks out a lot of radio signals. A lot of design decisions end up still needing a fairly complex shield to make sure that you're getting only the radio waves you are searching for.

        Arguably, you would want to place it near the lunar poles. Not for any of the BS arguments about the potential for water there, but because they have the least interference from Earth and the Sun. It also means you can survey the same stretch of sky for longer periods as out-of-plane bodies there are a lot easier to track and remain in the same cone of observation irrespective of the current lunar position. (ie, something that is at zenith over the lunar pole is not going to vary more than about 6 degrees from being overhead over the course of a year. Even something 25 degrees, or so, would still be visible pretty much all the time). If you go to lower latitudes, then it gets closer to a 14-day non-observation lineup followed by a 14 day period of variable observation from minimal to optimal and back as the object traverses the sky. The closer you get to the lunar equator, the more of the sky you will see, but the less the observation time and the more variable the quality of the observation.

        Ideally, they design a small inexpensive setup which can be done a few times on various areas of the Moon. Just choosing one set of criteria is going to be interesting. This is not like Hubble which can be pointed in any direction. There are a lot of rocks in the way.

          • Re: (Score:3, Interesting)

            by rijrunner (263757)
            The observatory does not have to be directly opposite the Earth. Just behind the edge would work. You could then run a fibre-optic cable to a location nearby that is visible to Earth.

    • If you really want to know... (Score:5, Informative)

      by TrekkieGod (627867) on Thursday February 21 2008, @07:50PM (#22510084) Homepage Journal

      The universe is a huge place, what makes NASA think that our telescopes are able to see the "earliest stars and galaxies"?

      The cosmic microwave background left over from the big bang as measured by WMAP [wikipedia.org] tells us the approximate age of the universe. Red-shift measurements tells us the distances of the stars we observe. The speed of light tells us how long it takes for the light of those stars to get here. Ta-da.

      Or is this one of those "We are in the center of the universe" ideologies again?

      We ARE at the center of the universe. So is everywhere else. The Big Bang wasn't an explosion that filled out existing space from which there's a center. Space itself expands from that point on, so the same infinitesimal point where the big bang started is the place where you're standing in now. The standard analogy is the surface area of a balloon as you fill the balloon up. There's just no preferred center.

    • Or is this one of those "We are in the center of the universe" ideologies again?

      From Ask an Astrophysicist [nasa.gov] :

      Question: If all the distant galaxies are flying away from us, does that mean that we're in the center of the Universe?

      Answer: Thanks for your question. Astronomers and physicists interpret the result that all distant galaxies are flying away from us as evidence for the uniform expansion of the Universe. In this case, any observer, at any location in the Universe, observes the same general motion: that the further a galaxy is from us, the faster its relative velocity with respect to the observer is. The famous (and very illustrative) example of this is to imagine a loaf of raisin bread as it is baking. The raisins in the bread spread away from one another as the loaf rises and expands during the baking. Pick any raisin and pretend you are standing on it (you're very small now!) and measuring the rate at which the other raisins are moving away from you. You will find that, no matter which raisin you choose, all other raisins appear to be moving away from you, with the furthest raisins receding the fastest.

      The current cosmological model of the Universe supposes that our position within the Universe is typical, not special. We are not located at the center of the Universe, but are rather taking part in its global expansion. I hope this answers your question.

      Regards,

      Padi Boyd
      for the Ask an Astrophysicist

      HTH.

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