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Moon NASA Science

Twin Probes Crash Into the Moon 79

Posted by timothy
from the as-promised dept.
SchrodingerZ writes "After their yearlong mission to map the Moon's gravitational field, twin probes Ebb and Flow crashed into the lunar surface, ending the GRAIL mission. The crashes were controlled events, each impacting 30 seconds apart from each other. The twin spacecraft were running low on maneuvering fuel and NASA, not wanting the craft to fall on historical sites such as the Apollo landing sites, redirected their flight patterns to impart the far (dark) side of the moon. Their impact sites were named after Sally Ride, the first American woman in space. 'During the news conference last week, Maria T. Zuber, the principal investigator, said the probes would be crashing into a "non-sunlit" part of the surface.' When the site becomes sunlit again in several weeks, the Lunar Reconnaissance Orbiter will attempt to take pictures of the craters the probes undoubtedly made in the lunar soil."
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Twin Probes Crash Into the Moon

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  • Far (dark) side? (Score:2, Informative)

    by Anonymous Coward on Tuesday December 18, 2012 @10:36AM (#42325233)

    The moon doesn't have a permanent dark side any more than the earth does!!!! The far side is in fact the mainly bright side during a new moon.

  • Dark != Far (Score:5, Informative)

    by tverbeek (457094) on Tuesday December 18, 2012 @10:40AM (#42325251) Homepage

    "redirected their flight patterns to [impact] the far (dark) side of the moon."

    Wrong. As TFA takes pains to explain, the "dark side of the Moon" and the "far side of the Moon" are not the same thing.
    An the impacts were on the near side of the Moon, while it is dark.

  • Re:Far (dark) side? (Score:5, Informative)

    by SternisheFan (2529412) on Tuesday December 18, 2012 @10:44AM (#42325311)
    You are correct. From the NY Times linked article: "In my article last week about the impending demise of Ebb and Flow, I noted, "Unfortunately, since the action will happen on the dark side of the Moon, there will be nothing for earthlings to see." About a gazillion people, including Robert Kirshner, a Harvard astronomy professor, wrote in to ask, "Didn't you mean to write 'far side' and not 'dark side'?" The more annoyed wrote: "Dark Side of the Moon??? Come on now. You know that is not correct! You completely blew a potential teaching moment, to educate the public that the **FAR** side of the Moon is **NOT** dark! Instead you perpetuated yet another scientific misconception. No wonder we are facing a crisis in science literacy in the U.S. The New York Times can and should do better!" Except I really meant, "dark side" -the side of the Moon facing away from the Sun. What was confusing to many was a remembered tidbit about the Moon, that there is always one face towards Earth, and the other always out of view, and they presumed that the crashes will be on the far side and therefore blocked from view. If that were the case, "far side" would be correct.

    A smaller number of readers wondered why the spacecraft will crash when the maneuvering fuel runs out. The Moon has no atmosphere and therefore there is no friction to slow them down. But the Moon's gravity is uneven and the orbit is not perfectly circular. Without periodic course adjustments, it will become more chaotic and elliptical, and the ellipse will intersect with the surface of the Moon -i.e., crash."

I am not now, nor have I ever been, a member of the demigodic party. -- Dennis Ritchie

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