PASADENA, Calif. — A NASA spacecraft built in Colorado fired its engine and slipped into orbit around the moon Saturday in the first of two back-to-back arrivals over the New Year’s weekend.
Ground controllers at the NASA Jet Propulsion Laboratory erupted in cheers and applause after receiving a signal that the probe was healthy and circling the moon. An engineer was seen on closed-circuit television blowing a noisemaker to herald the arrival.
“This is great, a big relief,” deputy project scientist Sami Asmar told a roomful of family and friends who gathered at the NASA center to watch the drama unfold.
The celebration was brief. Despite the successful maneuver, the work was not over. Its twin still had to enter lunar orbit on New Year’s Day.
The Grail probes — short for Gravity Recovery and Interior Laboratory — have been cruising independently toward their destination since launching Sept. 10 aboard a Delta II rocket provided by United Launch Alliance in Centennial.
The two washing machine-size spacecraft were designed and built by Lockheed Martin at its Waterton Canyon facility in Jefferson County.
Hours before Earth revelers counted down the new year, Grail-A flew over the south pole and slowed itself to get captured into orbit. Deep space antennas in the California desert and Madrid tracked every move and fed real-time updates to ground controllers.
Despite numerous missions to the moon, scientists don’t know everything about Earth’s nearest neighbor.
Why the moon is ever so slightly lopsided — with the far side more mountainous than the side that always faces Earth — remains a mystery. A theory put forth last year suggested that Earth once had two moons that collided early in the solar system’s history, producing the hummocky region.
Grail is expected to help researchers better understand why the moon is asymmetrical and how it formed by mapping the uneven lunar gravity field that will indicate what’s below the surface. Once in orbit, the near-identical Grail-A and Grail-B spacecraft will spend the next two months refining their positions until they are just 34 miles above the surface and flying in formation. Data collection will begin in March.
