NASA'S Twin GRAIL Spacecraft Reunite In Lunar Orbit


PASADENA, Calif. -- The second of NASA's two Gravity Recovery And
Interior Laboratory (GRAIL) spacecraft has successfully completed its
planned main engine burn and is now in lunar orbit. Working together,
GRAIL-A and GRAIL-B will study the moon as never before.

"NASA greets the new year with a new mission of exploration," said
NASA Administrator Charles Bolden. "The twin GRAIL spacecraft will
vastly expand our knowledge of our moon and the evolution of our own
planet. We begin this year reminding people around the world that
NASA does big, bold things in order to reach for new heights and
reveal the unknown."

GRAIL-B achieved lunar orbit at 2:43 p.m. PST (5:43 p.m. EST) yesterday.
GRAIL-A successfully completed its burn yesterday at 2 p.m. PST (5
p.m. EST). The insertion maneuvers placed the spacecraft into a
near-polar, elliptical orbit with an orbital period of approximately
11.5 hours. Over the coming weeks, the GRAIL team will execute a
series of burns with each spacecraft to reduce their orbital period
to just under two hours. At the start of the science phase in March
2012, the two GRAILs will be in a near-polar, near-circular orbit
with an altitude of about 34 miles (55 kilometers).

During GRAIL's science mission, the two spacecraft will transmit radio
signals precisely defining the distance between them. As they fly
over areas of greater and lesser gravity caused by visible features
such as mountains and craters, and masses hidden beneath the lunar
surface, the distance between the two spacecraft will change slightly.

Scientists will translate this information into a high-resolution map
of the moon's gravitational field. The data will allow scientists to
understand what goes on below the lunar surface. This information
will increase knowledge of how Earth and its rocky neighbors in the
inner solar system developed into the diverse worlds we see today.

Each spacecraft carries a small camera called GRAIL MoonKAM (Moon
Knowledge Acquired by Middle school students) with the sole purpose
of education and public outreach. The MoonKAM program is led by Sally
Ride, America's first woman in space, and her team at Sally Ride
Science in collaboration with undergraduate students at the
University of California in San Diego.

GRAIL MoonKAM will engage middle schools across the country in the
GRAIL mission and lunar exploration. Thousands of fifth- to
eighth-grade students will select target areas on the lunar surface
and send requests to the GRAIL MoonKAM Mission Operations Center in
San Diego. Photos of the target areas will be sent back by the GRAIL
satellites for students to study.

A student contest that began in October 2011 also will choose new
names for the spacecraft. The new names are scheduled to be announced
in January 2012. Ride and Maria Zuber, the mission's principal
investigator at the Massachusetts Institute of Technology in
Cambridge, chaired the final round of judging.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the
GRAIL mission for NASA's Science Mission Directorate, Washington. The
GRAIL mission is part of the Discovery Program managed at NASA's
Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin
Space Systems in Denver built the spacecraft.

For more information about GRAIL, visit:


Information about MoonKAM is available online at:



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