Friday, May 23, 2008

Lunar GRAIL will detail Moon's "Interiors"

From one of the many studies still being produced from Lunar Prospector (1998-99), this one by Alex S. Konopliv,, of NASA JPL, showing the complex discontinuities of the Moon's many centers of gravity. After the Lunar Reconnaisance Orbiter, NASA's GRAIL mission will provide finest detail yet of the lunar "interiors."

MIT professor of physics Maria Zuber is the principal investigator of the Gravity Recovery and Interior Laboratory — "GRAIL" for short. It's a new NASA mission slated for launch in 2011 that will probe the moon's quirky gravity field. Data from GRAIL will help scientists understand forces at play beneath the lunar surface and learn how the moon, Earth and other terrestrial planets evolved.

"We're going to study the moon's interior from crust to core," says Zuber. "It's very exciting."

For 270 days, beginning in September 2011, the GRAIL will be "twins," using interferometry turned inward for unprecedented detail of the complexities of the Moon's many interiors.

GRAIL will fly twin spacecraft, one behind the other, around the moon for several months. All the while, a microwave ranging system will precisely measure the distance between the two satellites. By watching that distance expand and contract as the two satellites fly over the lunar surface, researchers can map the moon's underlying gravity.

Scientists have long known that the moon's gravity field is strangely uneven and tugs on satellites in complex ways. Without course corrections, orbiters end their missions nose down in the moondust! In fact, all five of NASA's Lunar Orbiters (1966-1972), four Soviet Luna probes (1959-1965), two Apollo sub-satellites (1970-1971) and Japan's Hiten spacecraft (1993) suffered this fate.

Read MORE from Science@NASA HERE.

Excellent abstract and Study presentation (.pdf)
from the Lunar Science and Planetary Institutes 39th Conference (2008)

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