Using a NASA radar flying aboard India's Chandrayaan-1 spacecraft, scientists are getting their first look inside the moon's coldest and darkest craters.
The Mini-SAR instrument, a lightweight, synthetic aperture radar, has passed its initial in-flight tests and sent back its first data, NASA said.
The images show the floors of permanently-shadowed polar craters on the moon that aren't visible from Earth. Scientists are using the instrument to map and search the insides of the craters for "water ice".
"The only way to explore such areas is to use an orbital imaging radar such as Mini-SAR," said Benjamin Bussey, deputy principal investigator for Mini-SAR, from the Johns Hopkins University Applied Physics Laboratory.
"This is an exciting first step for the team which has worked diligently for more than three years to get to this point," he said.
The images, taken on November 17, 2008, cover part of the Haworth crater at the moon's south pole and the western rim of Seares crater, an impact feature near the north pole.
Further data collection by Mini-SAR and analysis will help scientists to determine if buried ice deposits exist in the permanently shadowed craters near the moon's poles.
"During the next few months we expect to have a fully calibrated and operational instrument collecting valuable science data at the moon," said Jason Crusan, programme executive for the Mini-RF Program for NASA's Space Operations Mission Directorate in Washington.
Mini-SAR is one of 11 instruments on the Indian Space Research Organization's Chandrayaan-1 and one of two NASA-sponsored contributions to its international payload.
The other is the Moon Mineralogy Mapper, a state-of-the-art imaging spectrometer that will provide the first map of the entire lunar surface at high spatial and spectral resolution.
Data from the two NASA instruments will contribute to the agency's increased understanding of the lunar environment as it implements America's space exploration plan, which calls for robotic and human missions to the moon, the agency said.
Chandrayaan-1 was launched from India's Satish Dhawan Space Center on October 21, 2008, and began orbiting the moon on November 8.