Oscar 4

Oscar 4 [Amsat]

Oscar 4 (Orbiting Satellite Carrying Amateur Radio 4) was a regular tetrahedron with edges 48 cm long. It had four independent monopole antennae and contained a tracking beacon transmitter and a communications repeater. It was powered by a solar cell array and batteries but an unplanned 161 km × 33000-km orbit prevented nominal use.

Oscar 4 was launched piggyback with three United States Air Force satellites on a Titan-3C. The launch vehicle had a partial failure and placed the spacecraft in a low orbit preventing widespread amateur use. Weight 18.1 kg. Four monopole antennas. OSCAR IV was built by the TRW Radio Club of Redondo Beach, California. It had a 3 Watt 10 kHz wide linear transponder (144 MHz uplink and 432 MHz downlink). In operation until March 16, 1966. Re-entry April 12, 1976. Total operation 85 days. Only about 12 two-way communications were established through the repeater, but one on December 22, 1965 was the first direct satellite communication between the United States and the USSR.