Wilkinson Microwave Anisotropy Probe (WMAP) (U.S.)
Destination: Solar orbit. Launched: June 30, 2001. Arrival: Oct. 1, 2001. Mission: To reveal conditions as they existed in the early universe by measuring the properties of cosmic microwave background radiation (CMB), the radiant heat left over from the Big Bang, over the full sky. Each sky scan takes approximately six months, and in April 2002, WMAP completed its first. The full sky map will be updated as more data is received and analyzed. Data from WMAP's first full sky scan was released in Feb. 2003, revealing a map of the oldest light in the universe, 13.7 billion years old.