NASA taps MIT to map moon

NASA said last week that MIT will lead a $375 million mission to map the moon and reconstruct its thermal history.

The mission, called the Gravity Recovery and Interior Laboratory (GRAIL) will put two separate satellites into orbit around the moon to precisely map variations in the moon's gravitational pull. These changes will reveal differences in density of the moon's crust and mantle, and can be used to answer fundamental questions about the moon's internal structure and its history of collisions with asteroids, NASA said in a statement.

The mission's technology is a direct spinoff from the current Gravity Recovery and Climate Experiment (GRACE) mission, which has been mapping Earth's gravitational field since 2002. GRAIL measurements of the gravitational field will come from very precise monitoring of changes in the distance between the two satellites, NASA said. The resulting measurements will map the moon's gravitational field up to 1,000 times more accurately than any previous mapping, NASA said. The main new technology needed to make GRAIL possible was a way to calibrate the timing of the satellites accurately, NASA said. The Earth-orbiting GRACE satellites use the GPS satellite navigation system, but there is no such system at the moon. Instead, the team adapted a technique that involves precise monitoring of radio signals originally designed for a different purpose for another planetary mission in development, named Juno.The same technology could be applied to future missions to map the gravitational fields of other interesting worlds such as Mars, where it could reveal the exchange of carbon dioxide between the polar caps and atmosphere or the movement of flowing subsurface water, NASA said.

The lunar gravity information will let any future manned or unmanned missions to land on the moon. Such data will be used to program the descent to the surface to avoid a crash landing and will also help target desirable landing sites, NASA said. The mission's technology could eventually be used to explore other interesting worlds such as Mars.NASA is looking to learn all it can about the moon. For example, such fundamental questions as whether or not the moon has a separate, differentiated core, as Earth does, are unknown, NASA said. GRAIL should also reveal details about lunar history, including the relative timing and effects of the myriads of huge impacts that created the craters and basins seen on the surface today.

The moon, with its airless, un-eroded surface, serves as a kind of Rosetta Stone for understanding the history of all the solar system's inner planets-Mercury, Venus, Earth and Mars-so the mission should also help to unlock secrets of the evolution of all these planets, NASA said.

The GRAIL satellites will be built and operated by Lockheed Martin Space Systems of Denver, Colo. NASA's Jet Propulsion Laboratory in Pasadena, Calif., will handle project management and development of the communications and navigation systems.