Findings with Gravity: NASA’s Upcoming Lunar GRAIL Mission January 20, 2011Posted by Nick Azer in : GRAIL, gravity, interior composition, mass concentrations (mascons), Raytheon, space conflict , trackback
NASA is launching a new lunar orbiter mission this year, and it’s one whose findings will carry a lot of gravity: the Gravity Recovery and Interior Laboratory (GRAIL)!
Utilizing nifty twin spacecraft, the mission (to be launched in Fall 2011) will map out the interior structure of the Moon in unprecedented detail, helping to reveal mysteries of its gravity and just how the Moon’s geologic thermal evolution unfolded.
A sister project of sorts to GRACE—successful twin satellites that have been measuring Earth’s gravitational fields since 2002—GRAIL is part of the NASA Discovery program, an initiative to develop smaller, cheaper, faster science missions to tackle objectives similar to more unwieldy missions of the past.
The Moon’s interior has been in the news lately; GRAIL’s findings will deepen (literally) this kind of knowledge, which could lend itself to understanding not just the Moon better, but also other bodies in the Solar System.
The findings will also help understand more about why the Moon’s gravity is “lumpy”. Yes, lumpy:
“The Moon is extraordinarily lumpy, gravitationally speaking. I don’t mean mountains or physical topography. I mean in mass. What appear to be flat seas of lunar lava have huge positive gravitational anomalies—that is, their mass and thus their gravitational fields are significantly stronger than the rest of the lunar crust.” -JPL planetary scientist Alex S. Konopliv, “Bizarre Lunar Orbits“, Nasa.Science.Gov
These lumps—called mass concentrations, or ‘mascons’—are tied to five maria on the near side. Why, exactly, is a mystery; one the GRAIL hopes to unravel.
Another interesting fold to the mission is the origin of the spacecraft design: the Airforce’s controversial XSS-11 satellite. Launched in 2005, the XSS-11 was seen by many as a step towards the U.S. military’s goal of ‘operationally responsive space’; the mission raised concerns that the design could later be used as a weapon to attack foreign satellites. (See Raytheon’s page on responsive space for more on the military concept.)
But, for now, we’ll be seeing the XSS-11 design put to peaceful (and awesome) use with the Moon. Success for GRAIL could open the door to more affordable missions across the solar system, and potentially more such practical missions to the Moon…and hopefully, with no costly satellite dogfights along the way. :)