2007 in spaceflight Moon. Japan's Kaguya orbiter, along with the smaller Okina and Ouna relay spacecraft, was launched on 14 September. The spacecraft entered Selenocentric orbit on 3 October. China launched its first Lunar probe, Chang'e 1, on 24 October, with the spacecraft entering Selenocentric orbit on 5 November. In 2009, two satellites launched into highly elliptical Earth orbits in 2007 as part of the THEMIS mission were also sent to the Moon. They are expected to arrive in October 2010. In August, the NASA Phoenix spacecraft was launched towards Mars, followed by the Dawn mission to the Asteroid belt in September. Cassini
Explorer 21 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 there was an 81.9-s