In early September 2011 NASA launched their twin GRAIL spacecraft towards the moon to map it’s gravitational field in unprecedented detail, and December 31st saw GRAIL-A enter into a 56-mile by 5,197-mile high lunar orbit at 5pm EST – GRAIL-B’s insertion burn is scheduled to begin January 1st at 5:05 p.m. EST.
“My resolution for the new year is to unlock lunar mysteries and understand how the moon, Earth and other rocky planets evolved,” said Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology in Cambridge. “Now, with GRAIL-A successfully placed in orbit around the moon, we are one step closer to achieving that goal.”
The GRAIL spacecraft were launched from Cape Canaveral Air Force Station’s Space Launch Complex 17 in Florida. The mirror-image craft were launched atop a United Launch Alliance Delta II rocket.
“With GRAIL-A in lunar orbit we are halfway home,” said David Lehman, GRAIL project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “Tomorrow may be New Year’s everywhere else, but it’s another work day around the moon and here at JPL for the GRAIL team.”
Video Courtesy of Jason Rhian
The real science work will begin in March. The spacecraft will transmit radio signals precisely defining the distance between them as they orbit the moon in formation. As they fly over areas of greater and lesser gravity caused by both visible features, such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.
The information & data gathered will translate into a high-resolution map of the moon’s gravitational field, allowing scientists to understand what goes on below the lunar surface and increase knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.