Overview

The Lunar CRater Observation and Sensing Spacecraft (LCROSS) will travel to the Moon as a co-manifested payload aboard the launch vehicle for the Lunar Reconnaissance Orbiter (LRO). The Mission Objectives of the LCROSS are to confirm the presence or absence of water ice in permanently shadowed craters at the Moon’s North or South Pole. LCROSS will also provide technologies and modular, reconfigurable subsystems that can be used to support future mission architectures.

The LCROSS mission delivers a 2000 kg impactor, to a lunar crater with a 10 km footprint accuracy, creating a 1000 metric ton plume of lunar ejecta—more than 200 times the energy of Lunar Prospector (LP). This ejecta plume will be visible from a number of Lunar-orbital and Earth-based assets. Water signatures will be measured with an in-situ Shepherding Spacecraft that follows the Centaur upper stage to the lunar surface. Designed to sense sub-surface regolith water concentrations to < 0.5%, LCROSS can leverage observations from Earth-based platforms and other lunar orbiting assets, such as LRO, Chandra, and the Hubble Space Telescope. Once observations are made by the Shepherding Spacecraft, it becomes a 700 kg impactor as well.

LCROSS will use the LRO launch vehicle’s spent Centaur upper stage as a kinetic impactor. The Centaur is maneuvered by a small “adapter” Shepherding Spacecraft (S-S/C) between the Centaur and LRO payload. After the LRO separates to head off to the moon for its own mission, the S-S/C guides the Centaur into a lunar impact trajectory, separates from the Centaur about 7 hours before impact, and follows the Centaur about 10 minutes behind. After Centaur impact, the S-S/C flies through the Centaur impact plume, while telemetering high resolution spatial and temporal measurements of the impact, plume and fresh Centaur crater. A campaign of ground-based observations will also be conducted to support and complement the S-S/C observations. The S-S/C itself becomes an impactor, impacting the Moon several km from the Centaur impact, which will be observed from Earth to provide important information about possible non-uniformity of hydrogen trapped in the shadowed craters.

The S-S/C approach to the mission leverages an existing high value asset, the Centaur, efficiently using existing space systems to obtain a high confidence measurement of lunar polar water ice concentration. The Lunar Gravity Assist, Lunar Return Orbit (LGALRO) orbit provides the necessary time to track, control and achieve a precision impact, while also achieving a high impact velocity and angle of incidence. The high incident impact provides an ideal plume that can be observed by the S-S/C and ground and space-based instruments.

NASA's Ames Research Center will oversee the development of the LCROSS mission with its spacecraft development and integration partner, Northrop Grumman.

Technical Information
Overview | Mission Rationale | Spacecraft and System Description | Instrumentation | Water Detection | Targeting
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