Gravitational waves and red shifts: a space experiment for testing relativistic gravity using multiple time-correlated radio signals

An experimental technique is described for detecting extremely low-frequency pulses of Gravitational radiation (#betta#GW approximately 1-10 mHz) originating from collapsing supermassive objects (M approximately 106-107 Msun) occurring anywhere in the universe. A highly stable hydrogen maser would be placed on board a deep-space probe that controls a transmitter sending signals to earth. The spacecraft also includes a doppler transponder operating in the conventional two-way mode. Doppler tracking using simultaneously acquired one- and two-way information both on the spacecraft and at the earth station provides four time-records of frequency fluctuations. A single gravitational disturbance manifests itself as a uniquely determined pulse sequence in the two or more data sets whose amplitudes and arrival times depend on a single parameter. The most likely of these gravitational pulse events occurring frequently enough to be detected (more than once per year) will come from the formation of black holes in the cores of ordinary spiral galaxies. A spaceflight is proposed with a highly eccentric earth orbit initially to measure the Gravitational red shift and second order doppler effects. Then it would go into a heliocentric orbit to search for Gravitational radiation. (U.K.)