A European Space Agency mission launched in 2009 to examine details of the cosmic background radiation that was the first electromagnetic radiation to fill the Universe after the Big Bang. Planck carried a telescope of 1.5 m diameter with detectors that mapped the cosmic microwave background with far greater resolution and sensitivity than before. It was positioned at the L2 Lagrangian point of the Earth's orbit, 1.5 million km from Earth in a direction opposite that of the Sun. Planck's results have helped evaluate important cosmological values such as the Hubble constant as well as elucidating the nature of the dark matter that dominates the present Universe. It was passivated in October 2013 and put into a heliocentric orbit.

The spacecraft is named after the German theoretical physicist and Nobel prize winner Max Planck.

http://sci.esa.int/planck/ European Space Agency site with information on all aspects of the Planck mission, including pages examining the fundamental questions Planck should help answer.