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Twin GRAIL Probes To Map Lunar Gravity Field

Posted by Soulskill on from the magnets-how-do-they-work dept.

smitty777 writes "The two washing machine sized satellites from the GRAIL program (Gravity Recovery and Interior Laboratory) launched in September are set to enter lunar orbit this weekend. As can be seen from this nifty infographic, the probes will monitor the gravitational field from orbit via the precise distance measurements of microwaves passing between the two satellites. From the article: 'The twin spacecrafts are named Grail-A and Grail-B. Grail-A will enter the moon's orbit on New Year's Eve, Grail-B will follow on New Year's Day. "The purpose of the GRAIL mission is to obtain gravity data on the Moon. And with that data, the scientists are able to determine the structure of the lunar interior, from crust to core," said David Lehman of NASA's Jet Propulsion Laboratory.' This is similar to the earlier GRACE project, which not only helped map out the gravity field of the Earth, but also helped map drought conditions in the U.S."

18 comments

  1. yuck by MichaelKristopeit421 · · Score: 0, Funny

    microwaved cheese is gross

  2. Twin GRAILs by Anonymous Coward · · Score: 0

    How Groovy!

  3. Nice! now we can know drought conditions on moon! by youn · · Score: 1

    wait, i think we kind of already know that :p... just stick to gravity field I guess haha :p

    --
    Never antropomorphize computers, they do not like that :p
  4. envisioned a washer and dryer in lunar orbit by Anonymous Coward · · Score: 0

    and now I cannot stop giggling

    1. Re:envisioned a washer and dryer in lunar orbit by g0bshiTe · · Score: 1

      Bout time, half my wardrobe is machine wash in a vacuum and tumble dry.

      --
      I am Bennett Haselton! I am Bennett Haselton!
  5. Re:Nice! now we can know drought conditions on moo by HornWumpus · · Score: 2

    You slay you.

    Somebody ought to.

    --
    John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
  6. Cool by Metabolife · · Score: 3, Informative

    These probes work by communicating with one another and measuring the slight changes in speed they experience as they orbit together. This change in speed correlates to a slow-down due to different gravitational pulls, hence lunar densities.

  7. Did anyone else... by Anonymous Coward · · Score: 0

    ...picture two flying space-washingmachines? :)

    1. Re:Did anyone else... by Ol+Biscuitbarrel · · Score: 1

      ARTHUR: Fine, um, I don't want to waste anymore of your time, but, uh
                  I don't suppose you could, uh, tell us where we might find a, um,
                  find a, uh, a, um, a uh--
          TIM: A what...?
          ARTHUR: A g--, a g--
          TIM: A GRAIL?!
          ARTHUR: Yes, I think so.
          KNIGHTS: Yes, that's it. Yes.
          TIM: Yes!
          KNIGHTS: Oh, thank you, splendid, fine.
                  [boom pweeng boom boom]

  8. September? by Anonymous Coward · · Score: 2, Interesting

    Did these probes take a really bad detour or something? If I read it right, they were launched in September, and are just getting into orbit around the moon at the end of this month. The Apollo missions made the same trip in a couple days. Why the incredibly long delay?

    1. Re:September? by CrankyFool · · Score: 3, Informative

      When you have to fly oxygen, food, and water to feed humans, you have to make the trip happen much faster -- and therefore burn way moe fuel -- than when you can take your time because the only thing you're consuming is electricity (and you can recover some of it via solar).

    2. Re:September? by nojayuk · · Score: 4, Informative

      The SMART-1 probe launched by ESA took about 13 months to reach Lunar orbit, propelled by a small ion engine and solar panels. Even then it started from a geostationary transfer orbit as a Getaway Special piggybacked on the commercial launch of two communications satellites via an Ariane 5.

    3. Re:September? by clj · · Score: 5, Informative

      Believe it or not, this long route (via the Earth-Sun L-1 (Lagrange-1) point is a lower energy trajectory (that is, it takes less energy to send the probes) than the more direct route followed by the Apollo missions. This allows for a smaller launcher (or conversely, a larger payload for the same sized launcher). See http://www.nasa.gov/pdf/582116main_GRAIL_launch_press_kit.pdf.

    4. Re:September? by Ol+Biscuitbarrel · · Score: 1

      I see that they're crashing both probes when their work is finished, too. NASA's really going skimpy on the delta V here.

  9. So many questions by Anonymous Coward · · Score: 0

    I've always wondered; what will happen to the moon when it leaves orbit? Where will it go? What will it do? And how will its magnetic field help/hinder its journey?

  10. Good by Anonymous Coward · · Score: 0

    When we start building condos and Wal Marts on the Moon, we have to know where is the best place to 3D print them.

  11. educational outreach as well by Anonymous Coward · · Score: 0

    the space craft are carrying 4 cameras each that they are connecting to middle schoolers around the world:
    http://moonkam.ucsd.edu

  12. GRAIL huh? by rueger · · Score: 1

    Beware the Holy Hand Grenade!

    --
    Three Squirrels