NASA?s Lunar Reconnaissance Orbiter is on track for its scheduled June 17 launch and its mission to gather more information about the moon?s poles and scout out safe landing sites for man?s return to the lunar surface.

The lunar orbiter is NASA's vanguard mission for the agency's plan to return humans to the moon by 2020 aboard its new Orion spacecraft and Altair lunar landers. It will launch along with its partner, Lunar Crater Observation and Sensing Satellite (LCROSS) which will slam into the moon's surface as part of a hunt for water ice.

LRO's launch has been delayed several times due to a crowded launch schedule, but is finally scheduled to take off next month aboard an aboard an Atlas V rocket.

Using a suite of seven instruments, LRO will help identify safe landing sites for future human explorers, locate potential resources, characterize the radiation environment and test new technology. LCROSS will seek a definitive answer about the presence of water ice in permanently shaded areas of the lunar poles.

"These two missions will provide exciting new information about the moon, our nearest neighbor," said Doug Cooke, associate administrator of NASA's Exploration Systems Mission Directorate in Washington, D.C. "Imaging will show dramatic landscapes and areas of interest down to one-meter resolution. The data also will provide information about potential new uses of the moon."

LRO's instruments will help scientists compile high resolution, three-dimensional maps of the lunar surface and also survey it in the far ultraviolet spectrum.

While the Apollo missions provided detailed maps of the moon's equatorial regions, good maps of the poles are lacking, said Craig Tooley, LRO project manager at NASA's Goddard Space Flight Center in Greenbelt, Md.

"We have much better maps of mars than we have of our own moon's polar regions," he said.

The satellite's instruments will help explain how the lunar radiation environment may affect humans and measure radiation absorption with a plastic that is like human tissue.

The probe's instruments will also allow scientists to explore the moon's deepest craters, look beneath its surface for clues to the location of water ice, and identify and explore both permanently lit and permanently shadowed regions.

"LRO is an amazingly sophisticated spacecraft," Tooley said. "Its suite of instruments will work in concert to send us data in areas where we've been hungry for information for years."

A NASA radar aboard India's Chandrayaan-1 spacecraft has already taken a glimpse inside the dark craters.

LCROSS will use the second stage Atlas Centaur rocket in a completely new way: The LCROSS Centaur will journey with the spacecraft for four months and be guided to an impact in a permanently shadowed crater at one of the moon's poles.

The resulting debris plume is expected to rise more than six miles. It presents a dynamic observation target for LCROSS as well as a network of ground-based telescopes, LRO, and possibly the Hubble Space Telescope.

Observers will search for evidence of water ice by examining the plume in direct sunlight.

LCROSS also will increase knowledge of the mineralogical makeup of some of the remote polar craters that sunlight never reaches.

"We look forward to engaging a wide cross section of the public in LCROSS' spectacular arrival at the moon and search for water ice," said LCROSS Project Manager Dan Andrews of NASA's Ames Research Center at Moffett Field, Calif. "It's possible we'll learn the answer to what is increasingly one of planetary science's most intriguing questions."

LRO will spend at least one year in low polar orbit around the moon, collecting detailed information for exploration purposes before being transferred to NASA's Science Mission Directorate to continue collecting additional scientific data.

The total cost of the entire mission, including launch delays, is $504 million, NASA officials said.