Gravitational-Wave Research Seminar

  Two geosynchronous gravitational wave mission concepts, generically   named gLISA, are discussed. One relies on the science instrument hosting   program onboard geostationary commercial satellites, while the other   takes advantage of recent developments in the aerospace industry that   result in dramatic satellite and launching vehicle cost reductions for a   dedicated geosynchronous mission.    To achieve the required level of disturbance free-fall onboard these   large and heavy platforms a "two-stage" drag-free system is proposed,   which incorporates the Modular Gravitational Reference Sensor (MGRS)   (developed at Stanford University) and does not rely on the use of micro-Newton  thrusters.    Although both mission concepts are characterized by different technical   and programmatic challenges, individually they could be flown and   operated at a cost significantly lower than those of previously   envisioned gravitational wave missions. We estimate both mission   concepts to cost less than 500M US$ each and we expect to perform at JPL   a detailed selecting mission cost analysis.  The resulting gravitational wave interferometers, whose arm-lengths are   both equal to about 73,000 km, can probe a frequency region (~ 3 x 10-2   - 10 Hz) complementary to those of longer baselines (such as   LISA/eLISA/NGO) and of ground detectors (LIGO, VIRGO).