A COLD ATOM CLOCK IN ABSENCE OF GRAVITY

We describe the operation of a cold atom clock in reduced gravity. We have recorded the cesium hyperfine resonance signal at a frequency nea r 9.2 GH in the similar to 10(-2) g gravity environment produced by je t plane parabolic flights. With a resonance width of 7 Hz, the device operated in a regime which is not accessible on earth. In the much low er gravity level of a satellite, our cold cesium clock would outperfor m the fountains with a potential accuracy of 5 x 10(-17). This experim ent paves the way to unprecedented performance in space applications s uch as tests of general relativity, global time dissemination, astrono my and geodesy.