NASA's GRAIL project spacecrafts, Ebb and Flow, crash-landed on the surface of the moon yesterday afternoon. The impact had been pre-planned, and occurred as predicted at 5:28 pm December 17, 2012. The landing site has been named in honor of Sally Ride, the first U.S. woman in space and a member of the GRAIL mission team.
"Sally was all about getting the job done, whether it be in exploring space, inspiring the next generation, or helping make the GRAIL mission the resounding success it is today," said Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology. "As we complete our lunar mission, we are proud we can honor Sally Ride's contributions by naming this corner of the moon after her."
The GRAIL probes were crashed into the moon at 1.7 kilometers per second (3,760 mph) because they had fulfilled their primary and extended missions, were low in orbit, and did not have enough fuel to be of any further use. The Sally K. Ride impact site, located on the southern face of a lunar mountain near Goldschmidt crater, was chosen to avoid the disturbance of U.S. and Russian historical sites scattered across the moon's surface.
The site was in shadow at the time of impact, so no images of the event were recorded. However, NASA's Lunar Reconnaissance Orbiter will be able to snap photos of the crash site in several weeks.
During their time in orbit, Ebb and Flow collected data that allowed scientists to create the highest-resolution gravity map of any celestial body.
"We will miss our lunar twins, but the scientists tell me it will take years to analyze all the great data they got, and that is why we came to the moon in the first place," said David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory. "So long, Ebb and Flow, and we thank you."
NASA provided live interviews and analysis by the GRAIL team in the moments leading up to the mission's destructive finale. A recording of the events can be seen below.