Ebb & Flow

Some of you may have seen the moon appear to go dark and then change colors last night. We have actually gotten a couple of calls about it and so for those of you wondering what happened last night this will answer your questions.

An artist’s depiction of the twin probes Ebb and Flow that comprise NASA’s Gravity Recovery and Interior Laboratory mission

Last night (December 17th, 2012), around 9:30pm GMT -6,  you may have (if you were lucky) seen a once in a life time sight. Last night the GRAIL (Gravity Recovery and Interior Laboratory), NASA mission came to an end.  The Ebb and Flow probes produced the highest resolution gravity map of any celestial body according to NASA. NASA said: “The map will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved”. The GRAIL science mission was NASAs first mission fully dedicated to education and public outreach. Many of images taken by the probes (at the request of many 4th – 8th graders) can be found here: NASA GRAIL MoonKAM Image Gallery.

GRAIL mission logo on the first stage of the Delta II rocket (Photo credit: Wikipedia)

English: The two GRAIL spacecraft took a long, counterintuitive but energy-saving route to the Moon by way of a point in space of relative gravitational stability called “Sun-Earth Lagrange point 1” (EL1). (Photo credit: Wikipedia)

The run down of last nights events you may have seen, if in the eastern US, is as follows according to my source at NASA. The GRAIL probes have reached the end of their operational lifetimes, and were unable to maintain the altitude required to continue their science mission. Last night, there was a very partial eclipse causing the darkness of the moon you would have seen and making this whole thing possible to be seen from earth. The probes, already in the process of burning out the remainder of their fuel supplies would have caused a slightly orangish light near the northern pole of the moon (remember only visible due to the slight eclipse). Once their fuel was expended, and reaching speeds of 6,051 kph (3,760 mph), the probes crashed into the surface of the moon. If you were lucky enough to see this happen last night consider yourself lucky.

NASA Animation of GRAIL impact

Related articles

• NASA’s Ebb and Flow spacecraft on final decent to Moon Impact (clarksvilleonline.com)
• NASA Probes Ebb & Flow Sent to Crash Into the Moon For GRAIL Project (z6mag.com)
• NASA’s Twin Probes Crash Into Moon (voanews.com)
• GRAIL Lunar Impact Site Named for Astronaut Sally Ride (spaceref.com)
• Two NASA probes crash into the moon (rawstory.com)

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