These measurements will allow us to fully deduce the interior structure of the Moon, from the crust to the core, and improve the understanding of the thermal evolution (the periods of heating and cooling) of our silver space companion. The knowledge acquired by GRAIL will be extended to the other planets of the Solar System,help determine the best landing site for any mission in the futureand provide us with a completehistory of asteroid collisions with the lunar surface.
In addition, according to María Zuber of the Massachusetts Institute of Technology (MIT) and principal investigator of GRAIL, the mission gained additional interest since the hypothesis was known that the Earth once had two moons that collided to form a single one. “GRAIL will shed light on this idea, explaining the reason for the asymmetry between the hidden and exposed faces”, he has advanced. “I hope this mission also explains the strange magnetization that rocks on its surface present,” Zuber adds. Not surprisingly, GRAIL will create the most accurate gravitational map of the Moon, improving our knowledge of the exposed face 100 times, and 1,000 times that of the far side. An extremely important information despite the fact that, as the researcher points out, “the Moon is the most studied rocky object in spaceand, unlike Earth, the geology of its surface preserves the record 4.5 billion years of history of the Solar System. “
Thetwo spaceships will fly one behind the other, with a separation of between 175 and 225 kilometers, at a height of just 50 kilometers, in almost circular polar orbits. During all that time a microwave system will accurately measure the distance between the two satellites. By watching that distance expand and contract as the two spacecraft fly over the lunar surface, the researchers will be able to map the Moon’s underlying gravitational field.
Scientists have known for some time that the Moon’s field of gravity is oddly uneven, and that it disturbs satellites in complex ways, causing those uncorrected to crash into the ground. In fact 12 previous lunar orbiters (from the United States, Russia and Japan) have suffered the same fate.
After fulfilling its scientific mission, GRAIL, who wears a “Moon Kam” so that the public can participate in the documentation, will also commit suicide – but on purpose – against the lunar soil.
Angela Posada-Swafford
