Friday, December 14, 2012

The HOLY GRAIL; NASA’s GRAIL spacecraft-Ebb & Flow

In September of last year NASA launched two spacecraft named Ebb & Flow (Orginally A & B). The probes are creating the highest resolution gravity map in the solar system. Their mission involves studying the interior of the moon and the gravitational anomalies that exist due to the varying areas of density.

Ebb & Flow constantly take measurements and note the changing distance between them via radio signals. When they fly over a gravitational anomaly the distance measured is altered and so following a series of orbits a map can be produced. NASA’s lunar Reconnaissance Orbiter provides the laser topographical measurements that when mingled with the gravitational anomalies form a more comprehensive map.

The moon is inactive and lacks any weather. Its current state is pretty much what it was billions of years ago. It lacks the constantly changing plates and the magma that is so destructive that Earth has obscuring of any evidence of its past. In fact the moon has in its crust cracks that extend down into the mantle as the GRAIL gravity survey would seem to suggest. (Its final report is not due until December 17th 2012)

So to summarize its mission is: • Map the structure of the crust and lithosphere • Understand the Moon’s asymmetric thermal evolution • Determine the subsurface structure of impact basins and the origin of mascons (high density regions on moon) • Ascertain the temporal evolution of crustal brecciation and magmatism (seismic and aseismic sliding) • Constrain deep interior structure from tides • Place limits on the size of a possible solid inner core NASA may have Mars on its mind but it is getting all the details right for the lunar site announced earlier this year.

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