The Wilkinson Microwave Anisotropy Probe (WMAP; also known as the Microwave Anisotropy Probe or MAP an Explorer 80) is a satellite mission to survey the sky and measure the temperature of the radiant heat left over from the Big Bang. The mission is led by Professor Charles L. Bennett of Johns Hopkins University, and is a joint project between NASA Goddard Space Flight Center and Princeton University. The satellite was launched by a Delta II rocket on June 30, 2001, at 19:46:46 GDT from the Kennedy Space Center in Florida. It is the successor to COBE and one of the series of medium-class (MIDEX) satellites in the NASA Explorer program. It is named after Dr. David Wilkinson, a member of the science team and pioneer in the study of cosmic background radiation, who died in September 2002.