By Irene Klotz
CAPE CANAVERAL, Fla., April 18 (Reuters) - A robotic U.S. spacecraft ended a pioneering mission to map dust and gases around the moon with a planned, kamikaze crash into the lunar surface early on Friday, NASA officials said.
The Lunar Atmosphere and Dust Environment Explorer, or LADEE, had been flying at increasingly lower altitudes to study how dust is lifted off the lunar surface and what gases comprise the moon's so-called exosphere - the region of space surrounding the airless moon.
NASA officials had planned to crash the spacecraft into the moon, after it transmitted its final batch of data.
Before hitting the lunar surface, LADEE was traveling at 3,600 mph (5,790 kph), three times faster than a high-powered rifle bullet, so the spacecraft not only broke apart upon impact, but pieces of it likely vaporized.
"There's nothing gentle about impact at these speeds," lead scientist Rick Elphic, with NASA's Ames Research Center in Moffett Field, California, said in a statement.
Launched on Sept. 6 from Wallops Island, Virginia,, LADEE put itself into orbit around the moon in October. After an instrument checkout and adjustments to its altitude, LADEE in November began what was originally expected to be a 100-day mission.
The mission was later extended to April 21, but LADEE ran out of fuel and came down somewhere on the far side of the moon between 12:30 a.m. and 1:22 a.m. EDT (1630 and 1722 GMT) on Friday, NASA said.
Flight controllers will try to figure out where exactly LADEE met its demise and use NASA's Lunar Reconnaissance Orbiter to image the site. The information will be the final bit of science from the mission about the lunar-space environment.
"It will be interesting to see what kind of (impact) feature LADEE has created," Elphic said.
In addition to better understanding the moon, scientists plan to use the data collected about the lunar exosphere to model the environments around other airless bodies, including the ice dwarf planet Pluto, which will be visited for the first time by a NASA spacecraft next year. (Editing by Alex Dobuzinskis and Jonathan Oatis)