NASA will launch two spacecraft to the Moon on Wednesday. One of them, the Lunar Reconnaissance Orbiter (LRO), will carry the Russian-made Lunar Exploration Neutron Detector (LEND). After making the four-day trip, it will orbit the Earth’s satellite at low altitude for about a year, making analyses to determine the presence of water. Then it will enter into a higher, more stable orbit, where it will remain for several more years.

The craft will be equipped with a total of six instruments and will also measure the solar and cosmic radiation that humans working on the Moon in the future will be exposed to. It will be launched by the same rocket as LCROSS, or the Lunar Crater Observation and Sensing Spacecraft, from Cape Canaveral. LCROSS will fire a probe into the Moon at a point near its pole that never receives sunlight and analyze the resulting plume of debris. Then LCROSS itself will crash into the Moon, producing debris for analysis by LRO.

LEND works on the same principle as HEND (High Energy Neutron Detector), the Russian instrument that found ice on Mars. Neutrons are released at different rates from ice and dry surfaces, and those rates are measured by the instrument. LEND is a joint project of six Russian institutes, NASA and three American universities. It was delivered to NASA by the Russian Academy of Sciences' Institute of Space Research.

The Atlas V rocket carrying the lunar craft is competing with the Endeavor space shuttle for launch time. The shuttle is currently grounded by a leak. It must take off by Saturday to deliver a part of the Japanese Kibo lab into orbit, or else wait for several months for the right conditions to occur again. Therefore, the Atlas V launch may be delayed, if repairs to the Endeavor are completed quickly.

The US has announced plans to send more men to the Moon by 2020. China has set the same year as a target for it to place astronauts on the Moon as well. Water on the Moon would make human habitation there logistically much easier.