In august 1995, two satellites created by human beings will be orbiting around the planet MARS. The spacecraft MARS OBSERVER, launched in Septembre 92, will be finishing its MARS accurate mapping mission, and the first Soviet satellite, MARS 94, will have just dropped small stations equipped with scientific probes onto the surface of MARS. Two years later, a second Soviet satellite will bring an additional set of experiments and balloons mainly equipped with cameras taking near pictures of the MARS surface during their trip in the Martian atmosphere. By shipping the so called "MARS BALLOON RELAY" telemetry equipment onto the US Spacecraft MARS OBSERVER, the French scientists will provide a redundant ling to collect and transmit the scientific data up to the Earth and to increase significantly in sapce and time, the collection of those data.