Planck is a space observatory operated by the European Space Agency (ESA), and designed to observe anisotropies of the cosmic microwave background (CMB) at microwave and infra-red frequencies, with high sensitivity and small angular resolution. The project, initially called COBRAS/SAMBA, is named in honour of the German physicist Max Planck (1858–1947), who won the Nobel Prize in Physics in 1918.
Built at the Cannes Mandelieu Space Center by Thales Alenia Space, and created as the third Medium-Sized Mission (M3) of the European Space Agency's Horizon 2000 Scientific Programme, Planck was launched in May 2009, reaching the Earth/Sun L2 point by July, and by February 2010 had successfully started a second all-sky survey. On 21 March 2013, the mission's all-sky map of the cosmic microwave background was released.
The mission complements and improves upon observations made by the NASA Wilkinson Microwave Anisotropy Probe (WMAP), which has previously measured the anisotropies at larger angular resolutions and much lower sensitivities. Planck also provides a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure.