NASA Grail Mission Twin Spacecraft to Ring in New Year’s Eve with Moon Orbit

According to a statement, NASA’s most recent mission to explore and study the moon will take place over New Year’s Eve and into New Year’s Day. The twin spacecraft for the Gravity Recovery And Interior Laboratory (GRAIL) mission are scheduled to perform their main engine burns to enter lunar orbit starting Saturday afternoon.

The first spacecraft, GRAIL-A is scheduled for its orbital entry burn at 4:21PM EST on December 31st, 2011 New Years Eve, while its twin GRAIL-B will fire its engines to begin its mission circling the moon on New Years Day at 2:05PM EST January 1st, 2012.

“Our team may not get to partake in a traditional New Year’s celebration, but I expect seeing our two spacecraft safely in lunar orbit should give us all the excitement and feeling of euphoria anyone in this line of work would ever need,” said David Lehman, project manager for GRAIL at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Once in orbit at a perch of about 34 miles (55 kilometers) above the moon’s surface, the two GRAIL spacecraft will begin a detailed scan which it designed to study the moon from crust to core. During their final approaches to the moon, both orbiters move toward it from the south, flying nearly over the lunar south pole.

While the spacecraft’s elliptical orbits will begin with a period of 11.5 hours. Over the following weeks, the GRAIL team will execute a series of burns to adjust it to just under two hours.

Using two spacecraft will allow scientists to take detailed measurements of the moon’s gravity. As they orbit, the spacecraft will transmit radio signals precisely defining the distance between them as they orbit the moon. As they fly over areas of greater and lesser gravity, caused both by visible features such as mountains and craters and by masses hidden beneath the lunar surface, they will move slightly toward and away from each other. An instrument aboard each spacecraft will measure the changes in their relative velocity very precisely, and scientists will translate this information into a high-resolution map of the Moon’s gravitational field.

Understanding the gravity fluctuations, will allow mission scientists to understand what goes on below the surface. This information will increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.

To follow the mission or read more about it, visit: http://www.nasa.gov/grail