Lunar water true, this would indicate that the neutron results from Lunar Prospector were primarily from hydrogen in forms other than ice, such as trapped hydrogen molecules or organics. Nevertheless, the interpretation of the Arecibo data do not exclude the possibility of water ice in permanently shadowed craters. In June 2009, NASA's "Deep Impact" spacecraft, now redesignated EPOXI, made further confirmatory bound hydrogen measurements during another lunar flyby. As part of its lunar mapping programme, Japan's Kaguya probe, launched in September 2007 for a 19-month mission, carried out gamma ray spectrometry observations from orbit that can measure the abundances of various elements
Explorer 21 on October 13, 1965 Explorer 21 Explorer 21, also called IMP-B and Interplanetary Monitoring Platform IMP-B, was an American satellite launched as part of Explorers program. Explorer 21 as launched on 27 November 1964 on Cape Canaveral, Florida, United States, with an Delta rocket. Explorer 21 was the second satellite of the Interplanetary Monitoring Platform. Explorer 21 was a solar cell and chemical-battery powered spacecraft instrumented for interplanetary and distant magnetospheric studies of energetic particles, cosmic rays, magnetic fields, and plasmas. Each normal telemetry sequence of 81.9 s in duration consisted of 795 data bits. After every third normal sequence