OSCAR 3

OSCAR III (a.k.a. OSCAR 3) is the third amateur radio satellite launched by Project OSCAR into Low Earth Orbit. OSCAR 3 was launched March 9, 1965 by a Thor-DM21 Agena D launcher from Vandenberg Air Force Base, Lompoc, California. The satellite, weighing 16.3 kg, was launched piggyback with seven United States Air Force satellites. The satellite employed no attitude control system. OSCAR III linear transponder lasted 18 days. More than 1000 amateurs in 22 countries communicated through the linear transponder. The two beacon transmitters continued operating for several months.[1][2]

OSCAR 3
Mission typeCommunications
OperatorProject OSCAR / DoD
COSPAR ID1965-016F
SATCAT no.1293
Spacecraft properties
Launch mass16.3 kilograms (36 lb)
Dimensions20 cm × 30 cm (7.9 in × 11.8 in)
Start of mission
Launch date9 March 1965, 18:29:47 UTC
RocketThor SLV-2 Agena-D
Launch siteVandenberg LC-75-1-2
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Eccentricity0.00227
Perigee altitude884 kilometers (549 mi)
Apogee altitude917 kilometers (570 mi)
Inclination70.1 degrees
Period103.1 minutes
Epoch9 March 1965
 

Project OSCAR

Project OSCAR Inc. started in 1960 with radio amateurs from the TRW Radio Club of Redondo Beach, California, many of whom worked at TRW and defense industries, 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 a “HI” greeting in Morse Code.

Project OSCAR was responsible for launching 3 other amateur radio satellites during the 1960s: OSCAR 1, OSCAR 2, and OSCAR 4

In 1969, AMSAT-NA was founded by radio amateurs working at NASA's Goddard Space Flight Center and in 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 III was an upgrade from the earlier Oscar I and Oscar II amateur satellites, three years earlier. Improvements included:

  • Oscar 3 was the first true amateur satellite relaying voice contacts in the VHF 2 meter band through a 1 W 50 kHz wide linear transponder (146 MHz uplink and 144 MHz downlink).
  • First amateur satellite to operate from solar power and relay signals from Earth.
  • First usage of beacon transmitters, separate from the main communications system (linear transponder).
  • Early Bird, also known as Intelsat I, the world's first commercial communications satellite, would be launched 28 days later.[4]

See also

References
  1. "Oscar 3". NASA National Space Science Data Center. 30 June 1977. Retrieved 15 February 2013.
  2. "OSCAR 3". 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.

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