Gérard Thuilliera, , , Steven Dewitteb, Werner Schmutzc and The PICARD team aService d'Aéronomie du CNRS, Bp 3, 91371 Verrières-le-Buisson, France bRoyal Meteorological Institute of Belgium, 3 Avenue Circulaire, B-1180 Brussels, Belgium cPhysikalisch-Meteorologisches Observatorium Davos, World Radiation Center, CH-7260 Davos Dorf, Switzerland Received 7 February 2005; revised 14 April 2006; accepted 22 April 2006. Available online 18 September 2006. Abstract A mission dedicated to simultaneous measurements of the solar diameter, spectral, and total solar irradiance is presently in development for launch end of the year 2008 on board of a microsatellite under the responsibility of Centre National d'Etudes Spatiales. The payload will consist of an imaging telescope, three filter radiometers with in total twelve channels, and two independent absolute radiometers. The scientific aims are presented as well as the concepts and properties of the instrumentation. This mission is named PICARD after the pioneering work of Jean Picard (1620–1682) who precisely determined the solar diameter during the Maunder minimum.