Space VLBI observations using the U.S. tracking and data relay satellite

VLBI observations using a satellite in earth orbit and ground antennas in Japan and Australia were conducted in 1986, 1987, and 1988. Sources were detected on space-ground baselines at both observing frequencies: 2.3 and 15 GHz. The coherence on space-ground baseline for 340 s was 90% at 2.3 GHz and 76% at 15 GHz. Brightness temperatures in the range 1 – 4 × 10 12 K were measured for 10 sources at 2.3 GHz and 6 sources at 15 GHz.