OSCAR 4

OSCAR IV (a.k.a. OSCAR 4) is the fourth amateur radio satellite launched by Project OSCAR and the first targeted for Geostationary orbit on 12 December 1965. The satellite was launched piggyback with three United States Air Force satellites on a Titan IIIC launch vehicle. The satellite was regular tetrahedron, 48 cm on each side. It had four independent monopole antennas and like OSCAR 3 contained a tracking beacon transmitter and a communications repeater. It was powered by a solar cell array and batteries.

OSCAR 4
Mission typeCommunications
OperatorProject OSCAR / DoD
COSPAR ID1965-108C
SATCAT no.01902
Spacecraft properties
Launch mass18.1 kilograms (40 lb)
Start of mission
Launch date21 December 1965 (1965-12-21)
RocketTitan IIIC 3C-8
Launch siteCape Canaveral LC-41
End of mission
Decay date12 April 1976 (12 April 1976)
Orbital parameters
Reference systemGeocentric
RegimeGeostationary (planned)
Eccentricity0.71843
Perigee altitude162 kilometers (101 mi)
Apogee altitude33,561 kilometers (20,854 mi)
Inclination26.80 degrees
Period587.4 minutes
Epoch20 December 1965
 

The launch vehicle suffered a partial failure and placed OSCAR IV in an unplanned 161 km × 33000-km orbit preventing the planned coverage. 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). The satellite remained in operation for 85 days, until March 16, 1966. The satellite eventually re-entered Earth's atmosphere on April 12, 1976. Only 12 two-way communications were established through the linear transponder, but one on December 22, 1965 was the first direct satellite communication between the United States and the USSR.[1][2]

Project OSCAR

Project OSCAR Inc. started in 1960 with the TRW Radio Club of Redondo Beach, California and radio amateurs who worked at TRW and other California defense companies, to investigate the possibility of putting an amateur satellite in orbit. Project OSCAR was responsible for the construction of the first Amateur Radio Satellite OSCAR-1, that was successfully launched from Vandenberg AFB in California . OSCAR 1 orbited the earth for 22 days, transmitting the “HI” greeting you see in Morse Code above.
Project OSCAR was responsible for launching of 3 other amateur radio satellites during the 1960s: OSCAR 1, OSCAR 2, and OSCAR 3.

In 1969, AMSAT-NA was founded by radio amateurs working at NASA's Goddard Space Flight Center and the Baltimore-Washington DC region, to continue the efforts begun by Project OSCAR.
Its first project was to coordinate the launch of Australis-OSCAR 5, constructed by students at the University of Melbourne.[3]

Today, over fifty years later, Project OSCAR still exists as part of the San Jose (CA) Amateur Radio Club. Its mission is “To initiate and support activities that promote the Satellite Amateur Radio Hobby”. The primary goal is to reach out and provide logistical support, training and in some cases equipment to amateur radio associations, schools and the public at large.

Firsts

Oscar IV was the first attempt for a High Earth Orbit (HEO) or GeoStationary Earth Orbit (GEO) amateur radio satellite, later categorized by AMSAT as Phase 3 and Phase 4.

Improvements included:

  • First higher power (3 Watt) 10 kHz wide linear transponder (144 MHz uplink and 432 MHz downlink), due to higher planned orbit.
  • First direct satellite communication between the United States and the USSR.
  • Successful development of innovative workaround procedures for satellite usage, based on launch vehicle partial failure.[4]
gollark: Still, it won't randomly deliver more power unless the device asks.
gollark: 100W, although I think there's a new standard now.
gollark: They worked fine without damaging things yesterday, but now anomalously started damaging blocks.
gollark: Does USB-C PD even go up to 130W?
gollark: What? High power should be negotiated.

See also

References
  1. "Oscar 4". NASA National Space Science Data Center. 30 June 1977. Retrieved 15 February 2013.
  2. "OSCAR 4". Gunter's Space Page. 31 December 1999. Retrieved 15 February 2013.
  3. "Space Satellites from the World's Garage – The Story of AMSAT". AMSAT-NA. Archived from the original on 5 October 2006. Retrieved 14 February 2013.
  4. Baker, Keith; Jansson, Dick (23 May 1994). "Space Satellites from the World's Garage -- The Story of AMSAT". Archived from the original on 5 October 2006. Retrieved 15 February 2013.

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

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