Oscar 1, 2

Oscar 1 (Orbiting Satellite Carrying Amateur Radio 1) was a quasi rectangular box, about 30 x 25 x 12 cm. The two approximately square surfaces were slightly curved, but were concentric with each other. One was slightly smaller than the other. A monopole transmitting antenna about 60 cm long extended from the center of the convex surface of the larger square. Reflective striping was applied for temperature control. This satellite was made by volunteer effort of a group of amateur radio operators and was launched as ballast on an AF launch vehicle. The spacecraft was battery operated and had no attitude control system.

The first Oscar Phase I amateur satellite was launched piggyback with Discover 36. A group of enthusiasts in California formed Project OSCAR and persuaded the United States Air Force to replace ballast on the Agena upper stage with the 4.5 kg OSCAR I package. The satellite was box shaped with a single monopole antenna and battery powered. The 140 mW transmitter onboard discharged its batteries after three weeks. 570 Amateurs in 28 countries reported receiving its simple 'HI-HI' morse code signals on the VHF 2 meter band (144.983 MHz) until January 1, 1962. The speed of the HI-HI message was controlled by a temperature sensor inside the spacecraft. OSCAR I re-entered the atmosphere January 31, 1962 after 312 revolutions

Oscar 2 was nearly identical. Differences included (1) changing the surface thermal coatings to achieve a cooler internal spacecraft environment, (2) modifying the sensing system so the satellite temperature could be measured accurately as the batteries decayed, and (3) lowering the transmitter power output to 100 mW to extend the life of the onboard battery. OSCAR II lasted 18 days ceasing operation on June 20, 1962 and re-entered June 21, 1962.

A third Oscar was designed, built, and tested, but was never launched. Similar in design to Oscar 1 and 2, Oscar* contained a 250 mW beacon with phase-coherent keying. Oscar* was never launched as the workers decided to focus their efforts on the first relay satellite - Oscar 3.

Last update: 27.09.2009
Contact: gunter.krebs@skyrocket.de
© Gunter Dirk Krebs