LADEE, NASA's mission to study the thin lunar atmosphere, came to a close on the far side of the Moon last night (US time), as its controllers had it smash into the lunar surface. NASA's policy is to treat the locations of the Moon landings as historical sites, and it takes pains to preserve them from possible damage. LADEE didn't have the fuel to control its orbit indefinitely. As a result, the controllers had been preparing to terminate the probe for several weeks.

The preparations included having it complete several orbits at an altitude below one mile, (1.6km), giving its scientific instruments a rare, close-up view of the Moon. In addition to its scientific missions, LADEE was used to test a new, laser-based communication system that set space bandwidth records: 622 megabits-per-second down from lunar orbit, with a 20mbps upload rate.

The exact moment of impact isn't clear, since the precise terrain it hit couldn't be determined in advance. (If it hit a ridge, it would have happened earlier than if LADEE plowed across a plain. What is clear is that the impact destroyed the probe.

"There’s nothing gentle about impact at these speeds," said Rick Elphic, a NASA project scientist. "It’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area." Once they analyze their data to get a firmer sense of the location, the Lunar Reconnaissance Orbiter will be directed to image the site.

We were lucky enough to have coverage of LADEE's launch in September 2013, so you can spend a moment admiring its liftoff.