Washington: Aimed at unlocking the mysteries
of the Moon, the first of the two NASA aircrafts entered the
lunar orbit, the American space agency has said.
NASA`s Gravity Recovery And Interior Laboratory (GRAIL)-A
spacecraft successfully completed its planned main engine burn
and began orbiting the Moon on Saturday.
A signal emitted by the probe indicated that it was
functioning properly and in place, according to officials at
NASA`s Jet Propulsion Laboratory in Pasadena, California.
The spacecraft is in a 56-mile (90-kilometer) by
5,197-mile (8,363-kilometer) orbit around the moon that takes
approximately 11.5 hours to complete.
GRAIL-A`s mirror twin, GRAIL-B is slated to enter the
lunar orbit on Sunday.
NASA said once both spacecraft are confirmed in orbit and
operating, science work will begin in March.
The spacecraft will transmit radio signals precisely
defining the distance between them as they orbit the moon in
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, it
NASA said 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," it said.
"This information will increase knowledge of how Earth
and its rocky neighbours in the inner solar system developed
into the diverse worlds we see on Sunday," NASA said.