COS B and Gemeaux S - Two experiments representative of the working methods employed at the CEN of Saclay

Project planning and organization is described for the COS B and Gemeaux S1 experiments, developed at the Centre d'Etudes Nucleaires at Saclay. The Gemeaux S1 experiment, borne aboard the Soviet Mars 6 and 7 probes, was designed to study the cosmic ray gradient between the earth and Mars. Various aspects of the experiment are discussed, including instrumentation, and project initiation and development. The COS B satellite experiment was designed to detect gamma rays from extraterrestrial sources. Emphasis is on the anticoincidence counter carried by the satellite. The use of 'Maison' (in-house) projects for space experiment planning at CEN is examined.