Science hits back at the moon

Last week NASA launched the Lunar Reconnaissance Orbiter (LRO) and the Lunar Crater Observation and Sensing Satellite (LCROSS). The LRO mission will map the lunar surface in greater detail than ever before, while LCROSS hurtles toward our nearest neighbour on a collision course, to deliver the scientific version of a double jab, two rapid blows that may uncover the existence of water on our otherwise rocky neighbour.

Launch of LRO and LCROSS. (Courtesy NASA)

Launched into space aboard an Atlas V rocket from Cape Canaveral last Thursday, these spacecraft will enter lunar orbit on Tuesday. LRO will eventually go into a circular orbit 50km above the moon's surface, while LCROSS will take up a highly elliptical orbit, which will culminate in a collision with the moon somewhere in the southern polar region, on the 9th of October this year. The exact location of the impact site will be decided based on further information from LRO.

NASA are looking for suitable landing sites for future manned missions to the moon, perhaps paving the way toward a manned lunar base. They have a particular interest in sites which are permanently in shadow, such as inside deep craters, because if water does exist on the moon, these are the most likely places to find it. They are also focusing their attention on the polar regions, because some areas there are almost constantly illuminated by the sun. This combination of water and near endless sunlight would make for some prime real estate, attracting potential developers of human habitats on the moon.

Among the suite of sensors aboard LRO, which include a camera and various radiation detectors, is the Lunar Orbiter Laser Altimeter (LOLA). This instrument will measure surface topography to build up a highly detailed 3 dimensional map of the lunar terrain, using a laser to measure ground elevation, slope angles and surface roughness. The Lyman Alpha Mapping Project (LAMP) will map the surface in the far ultraviolet, looking for evidence of surface ice while also imaging permanently shadowed regions which are only ever illuminated by starlight and interplanetary hydrogen emissions. Operating on the other side of the visible spectrum, the Diviner Lunar Radiometer Experiment (DLRE) will observe in the infrared portion of the spectrum, mapping the day and night time temperatures across the lunar surface. And to provide the high quality images that we'll all come to know and love, the craft has the Lunar Reconnaissance Orbiter Camera (LROC). One of its tasks is to image the Apollo landing sites and obtain information on recent micrometeorite impacts there, a natural hazard which future missions must be prepared for. All of these data will radically improve our understanding of the moon.

The LCROSS spacecraft will remain attached to the Centaur rocket which comprised the upper stage of the launch vehicle, until shortly before its brief mission commences. The two will then separate and LCROSS will watch as the spent rocket crashes into a region of the moon's surface which is in permanent shadow, before it then passes through the resulting plume of ejected material, taking further measurements of the debris.

The Total Luminance Photometer (TLP) aboard LCROSS will measure the impact flash, while cameras and spectrometers will continually make detailed measurements across the infrared and visible portions of the spectrum. With those tasks complete, the spacecraft will then end its mission a few minutes later by also crashing into the lunar surface, kicking up a second plume of material.

Ground and space based telescopes will be observing both of these impacts, as will the instruments aboard the LRO spacecraft. The plumes of debris will be illuminated by sunlight, revealing the mineralogical composition of the lunar surface and hopefully the tell-tale signs of that most precious of commodities, water.

Read more on LRO and LCROSS at the NASA web site:

Lunar Reconnaissance Orbiter

Lunar Crater Observation and Sensing Satellite