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LCROSS Targeting
LCROSS LGALRO OrbitImage right: Depiction of the Lunar Gravity-Assist, Lunar Return Orbit for a lunar south pole impact. Credit: NASA To maximize the creation of a debris plume, the impacts of the Centaur rocket and the LCROSS spacecraft need sufficient speed and a high angle of impact. Engineers have estimated that the Centaur and LCROSS spacecraft will impact the lunar surface at approximately 2.5 km/s or 5,592 miles per hour. The projected angle of impact is approximately plus or minus 70 degrees depending of the targeted pole.

To achieve this high angle of impact, the LCROSS spacecraft and the Centaur will execute a fly-by of the moon approximately five days after launch entering an extended Lunar Gravity-Assist, Lunar Return Orbit (LGALRO). This long looping orbit around the Earth will allow the Lunar Reconnaissance Orbiter possibly several months to collect science data about the lunar poles after engineers check out the orbiter's systems.

On final approach to the moon, the LCROSS spacecraft and the Centaur will separate. The spacecraft will perform a breaking maneuver and turn 180 degrees to orient the instrument payload to capture the Centaur impact. After the Centaur impacts, the LCROSS Spacecraft will have up to four-minutes of data collection and transmission to LCROSS mission control.

lunar gravity assisted orbit impactor arrivalImage right: Illustration of the final approach to the lunar south pole. Credit: NASA