NASA’s twin GRAIL spacecraft concluded their mission with one final scientific study as they were purposely guided into a ridge near the moon’s north pole. The impact occurred at 5:29 p.m. EST on Monday, December 17, 2012, with each craft expected to strike the moon’s surface about 30 seconds and one-and-a-half miles apart.
The site has been approved by NASA to be named after astronaut Sally Ride, who led the mission’s MoonKam payload and passed away in 2012. The MoonKam provided outreach to middle school students through the use of a camera placed on each spacecraft.
GRAIL had been in orbit of the moon mapping its gravitational field, as well as discovering new details about the lunar interior and revealing the moon’s crust is not as thick as previously expected.
“The knowledge of the gravitational field is now so accurate that, in the future, NASA and commercial missions will be able to navigate much more accurately [when] we land or fly over the moon,” said Charles Elachi, director of the Jet Propulsion Lab in California.