NASA Probes Ebb and Flow ended their space mission with a crash on Monday.
The crash occurred as planned with both probes crashing into the moon one after another at 5:28 PM EST. The two probes had been circulating the moon to help secure new information on its structure and composition. They had been launched as part of the Gravity Recovery and Interior Laboratory, or GRAIL which started back in September 2011. The probes had been revolving around the moon since January 1, 2012.
"We do feel the angst about the end of the mission," said Charles Elachi, director of NASA's Jet Propulsion Laboratory in Pasadena, California. "On the other hand, it is a celebration because this mission has accomplished tremendous science."
"We'd hoped for another six months lifespan for GRAIL, but it was not to be," added project manager David Lehman of NASA's Jet Propulsion Laboratory. "It's going to be emotional; I've brought a handkerchief just in case."
The site of the crash was named after Sally K. Ride, the first U.S. woman to enter space in 1983, and also the person who organized GRAIL's educational outreach program. She died this past July of pancreatic cancer.
According to Reuters, there are other studies and missions planned including one which will coordinate the moon's new gravity maps with the locations where Apollo soil and rock samples were collected.