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NASA's twin GRAIL spacecraft now together in lunar orbit


January 2, 2012

Artist concept of GRAIL-B performing its lunar orbit insertion burn to join GRAIL-A in lunar orbit (Image: NASA/JPL-Caltech)

Artist concept of GRAIL-B performing its lunar orbit insertion burn to join GRAIL-A in lunar orbit (Image: NASA/JPL-Caltech)

Nasa's twin GRAIL (Gravity Recovery And Interior Laboratory) spacecraft are now in orbit around the Moon. Having achieved lunar orbit at 2 p.m. PST on New Year's Eve, GRAIL-A was joined by GRAIL-B at 2:43 p.m. PST on New Year's Day. The twin spacecraft are now in a near-polar, elliptical orbit with an orbital period of approximately 11.5 hours. In readiness for the science phase of the mission which is due to start in March 2012, both spacecraft will undergo a series of burns in coming months to place them in a near-polar, near-circular orbit with an altitude of about 34 miles (55 km) and orbital period of just under two hours.

GRAIL's science mission will see the twin spacecraft orbiting the Moon in formation and transmitting radio signals that will allow the distance between them to be precisely measured. By measuring the changes in distance between the spacecraft caused by the changes in gravity as they pass over visible features such as mountains and craters, and masses hidden beneath the lunar surface, scientists will be able to create a high-resolution map of the Moon's gravitational field. This will allow scientists to determine the inner structure of the Moon and aid in the understanding of the evolution of Earth and its rocky neighbors in the inner solar system.

As part of the MoonKAM (Moon Knowledge Acquired by Middle school students) program, each GRAIL spacecraft also carries a small camera that will allow thousands of fifth- to eighth-grade students to select target areas of the lunar surface for MoonKAM snapshots that will be sent back by the GRAIL satellites for the students to study. By then, the GRAIL spacecraft will also have new names as the result of a student contest - the results of which are due to be announced some time this month.

Source: NASA


After submissions from nearly 900 classrooms with more than 11,000 students from 45 states, Puerto Rico and the District of Columbia, the entry from a class of fourth graders from the Emily Dickinson Elementary School in Bozeman, Montana has been selected as the winner of the contest to name the twin GRAIL spacecraft. GRAIL-A and -B have now been christened "Ebb and Flow."
About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

My wish for 2012 is that these Spacecraft (or just one of them) can further prove that the Apollo missions were for real. It would really make me happy and smile from ear to ear to prove the naysayers wrong


will messing with the moon say paving it or planting on it reduce reflection of the suns rays effecting the earths temp or...?

Jay Finke

bf_308, haven\'t you seen the high def photos of the landing sites, taken recently by a lunar orbiter. They look very convincing to me.


The moon landings were fake - let me assure you.

I was there and they never arrived at the sites.

Mr Stiffy
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