2007 in spaceflight 2007 in spaceflight The year 2007 contained several significant events in spaceflight, including a Chinese ASAT test, the launches of the US Phoenix and Dawn missions to study Mars and Asteroid belt respectively, Japan's Kaguya Lunar orbiter, and the first Chinese Lunar probe, Chang'e 1. The internationally accepted definition of a spaceflight is any flight which crosses the Kármán line, 100 kilometres above sea level. The first recorded spaceflight launch of the year occurred on 10 January, when a PSLV, launched from the Satish Dhawan Space Centre, placed four spacecraft into low Earth orbit. One of these spacecraft was SRE-1,
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