PLANCK is an astronomy mission being flown as part of the ESA scientific program. Planck has two instruments in its focal plane, one of which is the High Frequency Instrument (HFI). The HFI was developed by a partnership between the CNES and several international laboratories, which the Institute of Space Astrophysics (IAS) in Orsay, France, acting as prime contractor.

Planck was designed to study the origin and evolution of the Universe in the submillimeter range of the electromagnetic spectrum. It will map the anisotropies, or small variations from place to place on the sky, of the Cosmic Microwave Background (CMB), which is an "afterglow" of the Big Bang which fills all of space and has a temperature of 2.73 K. Planck will make measurements with an angular resolution of about 5 arcminutes (which can be compared to the 13 arcminutes of its predecessor, WMAP) and a temperature sensitivity of about two parts per million.

On November 19 2010, ESA's Science Program Committee approved an extension of Planck mission operations until December 31 2014, subjected to a mid-term review in 2012.