Catch up on stories from the past week (and beyond) at the Slashdot story archive

 


Forgot your password?
Close
typodupeerror
×
Moon NASA Space Science

GRAIL Mission Video Released 36

Posted by Soulskill from the stately-grace dept.
SchrodingerZ writes "A new video was released yesterday by NASA from the GRAIL mission probes, which ended their mission last month as they impacted the lunar surface. 'Dramatic' footage was captured by the probe Ebb on December 14th. The video was taken from the 'MoonKAM (Moon Knowledge Acquired by Middle school Students) cameras. It shows the view of Ebb flying at an altitude of 6 miles (10 km) above the Moon's northern hemisphere in the vicinity of Jackson crater (22.4N 163.1W).' Two videos were released, one from the fore and one from the aft of the probe, showing a forwards and backwards time lapse containing 931 and 1,489 pictures each of the lunar terrain. The footage was part of the probes' final systems check before they shut down and were sent into a controlled impact to a predetermined location."

This discussion has been archived. No new comments can be posted.

GRAIL Mission Video Released More

GRAIL Mission Video Released

Comments Filter:

  • What pants were they wearing when they hit the moon?

  • ..an iPhone? What's with the weird aspect ratio? Also, this is amazing.

  • Probably limited by data transmission bandwidth and signal reception.

  • Ask Slashdot question in the making... (Score:5, Interesting)

    by jeffmeden ( 135043 ) on Friday January 11, 2013 @04:45PM (#42562285) Homepage Journal

    Hey armchair astrophysicists... A thought occurred to me when watching this video. Since the moon has a negligible atmosphere, how close can a spacecraft reliably orbit it? Other than the ability to make sure eccentricity is near 0, what would stop a satellite from orbiting a few hundred meters above the tallest peak?

    • Re:Ask Slashdot question in the making... (Score:4, Informative)

      by tjp ( 264994 ) on Friday January 11, 2013 @05:05PM (#42562473)
      The whole purpose of this mission was to measure the variations in the moon's gravity by flying at a very low altitude. Consequently, those gravitational variations introduced changes in the orbit requiring relatively frequent corrections. It follows that the closer you orbit, the more actively you'll have to work to maintain that orbit. When you fly low over a mountain, the extra mass in that area will pull you down, and you'll have to correct for that with upward thrust.

      The moon's uneven gravity field presents a challenge to ground controllers planning trajectories for low-altitude lunar orbiters. The tug of lunar gravity can alter a satellite's orbit, requiring frequent rocket burns to adjust the spacecraft's path around the moon.

      Spaceflight Now, March 21, 2012 [spaceflightnow.com]

    • Re: (Score:1)

      by Tablizer ( 95088 )

      negligible atmosphere...what would stop a satellite from orbiting a few hundred meters above the tallest peak?

      A small error in navigation :-)

      Essentially that's what they did to (intentionally) crash it. It hit a mountain side almost completely horizontally.

    • Re: (Score:1)

      by Anonymous Coward

      The serious answer is that the lunar mass is not uniformly distributed. The second-and-higher order gravitational anomalies will perturb a circular orbit into an elliptical one. Eventually, the semi-minor axis of the elliptical orbit will equal the lunar radius, and the spacecraft will crash.

      For reference, LRO spent almost two years in a mostly-circular orbit at 50 km altitude above the surface. Every two weeks or so they had to perform a maneuvering burn to maintain the circular orbit. At the end of th

    • Re:Ask Slashdot question in the making... (Score:4, Insightful)

      by DerekLyons ( 302214 ) <fairwater.gmail@com> on Friday January 11, 2013 @05:13PM (#42562567) Homepage

      You can't reliably orbit the moon at low altitude without a large supply of fuel to keep reboosting your orbiter. Because of mascons [wikipedia.org], the moon's gravitational field is very "lumpy" (has regions of higher and lower gravity) and thus such orbits are unstable.

    • Re: (Score:1)

      by M1FCJ ( 586251 )

      Short answer: If the moon was a perfectly uniform sphere with a perfect gravity gradient (as you would assume in in high-school physics), yes. In real life, the moon is seriously lumpy and that plays havoc with the long-term low-altitude orbits.

  • I mean, magnetometer data is good and necessary and all, but this is the kind of thing that really ignites the imagination and sparks interest.

    Also NASA, try to remember to turn your phone sideways when shooting video. It's ok, I do it too sometimes.

  • I cant wait for the data to be interpolated and released from these missions. It has allot of potential to answer questions about the moon. Its probably the single most interesting experiment I can think of. It might even tell us if theres pockets of material buried in specific areas much like they used it to monitor earths aquifers.

  • One can do 400m in KSP [kerbalspaceprogram.com]. If you're not snapping off spaceship parts you're too far away.

  • "Where's the Kaboom!? There's supposed to be a moon-shattering Kaboom!" -MM

  • The footage was part of the probes' final systems check before they shut down and were sent into a controlled impact to a predetermined location.

    Why shut anything down? Granted, they may not be able to see much since the impact was on the night side but I don't see what harm there could be in keeping the camera rolling until it's explosive decommissioning.

    • Because NASA doesn't want you to know the TRUTH! That "probe" is on a laundry line coasting over a movie set in Area 51! Know why the video is so short? They ran out of hangar floor space that's why. I've got a cousin in New Mexico he told me ALL about it...

  • STAY ON TARGET
  • A thought just occurred.

    There's often talk about whether there is a lot of Helium-3 under the surface of the moon since the astronauts brought back rocks containing lots of it. Shouldn't this helium show up in a spectrum analysis of the dirt plume from the crash?

    • If the wavelengths can be interpolated from the data. So far it looks like 2 channel binary black and white. So I doubt it in this case.

  • This is a rework of the GRAIL’s moon shots along with gravity maps created from the data acquired, enjoy it http://www.youtube.com/watch?v=TX8nKojIiHI [youtube.com]

Slashdot Top Deals

news: gotcha

Close