14 DAY TRIAL // Officials at the American space agency announced yesterday, January 17, that they now have new names for the two GRAIL (Gravity Recovery And Interior Laboratory) spacecraft currently orbiting the Moon. The probes arrived in lunar orbit on December 31, 2011 and January 1, 2012, respectively.
Their new names were submitted by fourth graders from the Emily Dickinson Elementary School, in Bozeman, Montana. They argued that GRAIL-A should be renamed “Ebb,” while GRAIL-B should be known as “Flow.” Apparently, NASA officials thought the names representative of the mission, too.
The purpose of the GRAIL spacecraft is to create a highly-detailed map of the lunar gravity field. This is made possible by a very complex, laser-based, distance-measuring instrument aboard both probes.
As they are flying in close formation above the lunar surface, slight variations in the Moon's gravitational pull – caused by underground hollows, magnetic deposits, mountains, and so on – change the trajectory of the leading spacecraft by a small margin.
This also leads to a slight change in the distance the two probes fly from each other. The instruments aboard Ebb and Flow are capable of translating these very small variations in distance into complex data products on how the Moon's gravity works.
The contest through which NASA sought to rename the spacecraft began in October 2011. The new names were selected from those proposed by nearly 900 classrooms. NASA says that 11,000 students from 45 states, Puerto Rico and the District of Columbia, were a part of the effort.
“The 28 students of Nina DiMauro's class at the Emily Dickinson Elementary School have really hit the nail on the head,” explains the principal investigator of the GRAIL mission, Massachusetts Institute of Technology (MIT) professor Maria Zuber.
“We were really impressed that the students drew their inspiration by researching GRAIL and its goal of measuring gravity. Ebb and Flow truly capture the spirit and excitement of our mission,” she adds.
Zuber and America's first woman in space, Sally Ride, made up the committee that selected the most appropriate name for the probes, out of the 890 proposals students around the country submitted online.
“With submissions from all over the United States and even some from abroad, there were a lot of great entries to review. This contest generated a great deal of excitement in classrooms across America, and along with it an opportunity to use that excitement to teach science,” Ride says.