A United Launch Alliance Atlas V will depart Launch Complex 41 here at Cape Canaveral Air Force Station at 5:22 pm EDT today. Two more one minute launch windows follow at 5:22 and 5:32 pm also.
Weather is only 60% forecast GO for today due to late day thunderstorm build up.
The two satellites called LRO (Lunar Reconnaissance Orbiter) and LCROSS (Lunar CRater Observation & Sensing Satellite) will begin a multi month mission. LRO will map in high resolution the Lunar surface as NASA works to select a landing sight for a possible 2020 manned landing.
Meanwhile, LCROSS will haul the Atlas' centaur upper stage to Lunar orbit. For four months, LCROSS will swing around the moon before releasing centaur and allowing it to crash into a dark crater at the south pole. When the lunar dust is kicked up from the impact, LCROSS will swing through looking at the chemical make up the soil.
NASA will be looking for signs of moisture in the lunar dust which had been sitting quietly in a dark crater for millions of years.
About five minutes after centaur crashes, LCROSS will also make it's impact of the mission as it crashes into the lunar surface this October.
The two impacts will have NASA turn the newly refurbished Edwin Hubble Space Telescope and several earth based telescopes aimed at the lunar south pole to record the plume.
NASA's Ames Research Center will over see the mission, including the instrumentation.