The Lunar Reconnaissance Orbiter (LRO), launched last week to survey the moon with an eye toward future human exploration, has reached lunar orbit. The spacecraft entered orbit today at 6:27 A.M. (Eastern Daylight Time), placing a NASA probe around the moon for the first time in nearly 10 years.

From its orbit 31 miles (50 kilometers) above the moon, LRO will make detailed maps of the lunar surface, including its poles, where astronauts would have access to consistent solar power and possibly even stores of water ice. A companion spacecraft launched with LRO, the Lunar Crater Observation and Sensing Satellite, or LCROSS, will make two lunar impacts this fall to seek out evidence of that water. LRO will contribute to that water hunt while also studying the moon's radiation environment and its potential health effects, among other investigations.

LRO joins a similar mission, India's Chandrayaan-1 spacecraft, already in lunar orbit. Chandrayaan-1 carries a Mini-RF radar instrument, just as LRO does, and featured a lunar impactor probe that struck the moon in November.

Photo of LRO/LCROSS liftoff last week: NASA/Sandra Joseph, Tony Gray