It's Almost Time Moon Impact

It's been over three months since the Atlas V soared from Cape Canaveral, Fla. into space carrying the Lunar Reconnaissance Orbiter (LRO) and the Lunar Crater Observation and Sensing Satellite ("LCROSS" for short). Now it's finally time for LCROSS to do its things and get up close and personal with the moon.

An artist's interpretation of NASA's LCROSS spacecraft observing the first
impact of its rocket booster's Centaur upper stage before heading in for its
own crash into the moon's south pole. Credit: NASA

On Oct. 9 beginning at 6:30 a.m. CDT, the LCROSS spacecraft and heavier Centaur upper stage rocket will execute a series of procedures to separately hurl themselves toward the lunar surface to create a pair of debris plumes that will be analyzed for the presence of water ice. The Centaur is aiming for the Cabeus crater near the moon's south pole and scientist expect it to kick up approximately ten kilometers (6.2 miles) of lunar dirt from the crater's floor.

Image of NASA's Infrared Telescope Facility. Credit: NASA

The sun never rises above certain crater rims at the lunar pole and some crater floors may not have seen sunlight for billions of years. With temperature estimated to be near minus 328 degrees Fahrenheit, these craters can 'cold trap' or capture most volatiles or water ice.

Earth-based radar image of the North Pole of the Moon, showing the position of the crater
Erlanger (arrow). Photo: Arecibo Observatory and NASA

On the day of impact, LCROSS at approximately 40,000 kilometers (25,000 miles) above the lunar surface will spin 180 degrees to turn its science payload toward the moon and fire thrusters to slow down. The spacecraft will observe the flash from the Centaur's impact and fly through the debris plume. Data will be collected and streamed to LCROSS mission operations for analysis. Four minutes later, LCROSS also will impact, creating a second debris plume.