After more than a decade's absence, NASA made its first steps back to the moon June 18, launching two lunar spacecrafts atop an Atlas V rocket. The Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Spacecraft are unmanned scouts designed to lay the first groundwork for NASA's proposed 2020 return of astronauts to the moon.
The launch went off without a hitch at 5:32 p.m. EDT, powered by two liquid-fueled engines and a pair of solid-fueled boosters.
While the LRO and LCROSS are traveling to the moon together, they'll take vastly different paths once there.
LRO will go into orbit 31 miles above the moon's surface, mapping the moon in high resolution for future landing sites and to gather crucial data on the lunar environment that will help astronauts prepare for long-duration lunar expeditions.
LCROSS will guide an empty 2.5-ton upper stage of the launch rocket on a collision course with a permanently shaded crater in an effort to kick up evidence of water at the moon's poles. NASA will scan the collision dust and debris for future study. LCROSS itself will also impact the lunar surface during its course of study.
The primary focus of the mission will be to study the moon's relatively unexplored and extremely cold polar regions. The temperatures at the poles are approximately 370 degrees below 0 Fahrenheit, cold enough to trap water ice. The Apollo missions revealed that lunar rocks are very dry, but did not provide information about the polar regions, where water is most likely to exist.
One of the instruments aboard the LRO is the Diviner Lunar Radiometer Experiment, which will make the first global survey of the temperature of the lunar surface while the orbiter circles above the moon.
"The terrain on the far side of the moon is quite different from that of the near side of the moon," David Paige, principal investigator for the Diviner instrument at UCLA, said in a preflight interview. "The more we learn about the moon, the better scientific questions we can pose, and the better locations we can find for future lunar landings for robotic and human explorers. By getting a comprehensive view, NASA can tailor future landing sites to specific goals."
Based largely on the Mars Climate Sounder Instrument flying aboard the Mars Reconnaissance Orbiter, Diviner is a nine-channel radiometer. The instrument will be capable of measuring very cold temperatures, and will, for the first time, characterize the entire thermal environment of the moon. Diviner will also produce a map showing the composition of the moon and a map showing how rocky the moon is.
"We don't really know what we will find when we explore the polar regions thoroughly," Paige said.