- AMSAT-OSCAR 7
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AMSAT-OSCAR 7 Launch date 15 November 1974 Launch vehicle Delta 2310 Launch site Vandenberg AFB, Lompoc, CA USA COSPAR ID 1974-089B Mass 28.8 kg (63 lb) Orbital elements Regime Low Earth Orbit Inclination 101.59° Altitude 1,459 km (907 mi) AO-7 (aka AMSAT-OSCAR 7) is the second Phase 2 amateur satellite launched into Low Earth Orbit on 15 November 1974. It remained operational until a battery failure in 1981. On 21 June 2002 the satellite was heard again on its 2 meter beacon (145.9775 MHz CW) after 21 years of silence, and 27 years in space.[1]
AMSAT reported AO-7 still semi-operational on 6 April 2006, with reliable power only from its solar panels; the report stated the cause of the outage was a short circuit in a battery and the restoration of service was due to its becoming an open circuit. The satellite eclipses on every orbit during the northern summer and autumn; the rest of the year it is in continuous sunlight and alternates between transmission modes A and B.[2]
Contents
Firsts
AO-7 demonstrated several uses of new technologies and operations [3]
- First satellite-to-satellite relay, through AO-6.[4]
- Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were carried out using this satellite.
- The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology developed by Dr. Karl Meinzer as part of his Ph.D.
- First to fly a Battery Charge Regulator (BCR).
Legal issues
The uplink frequency predates the WARC 1979 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service which places the uplink in the 70cm weak signal segment. Additionally, the IARU bandplan has the 432.1 MHz range (which is used for mode B uplink) marked for "weak signal" in all three Regions.
Current status
As of August 2011[update], contacts with AO-7 are reported daily.[5]
References
- ^ "ARRLWeb: It's Aliiiiive! AMSAT-OSCAR 7 Satellite Returns from the Dead". American Radio Relay League. 24 June 2006. Archived from the original on 4 November 2005. http://web.archive.org/web/20051104135636/http://www2.arrl.org/news/stories/2002/06/24/101/. Retrieved 26 September 2010.
- ^ "AMSAT - Satellite Detail - AMSAT-OSCAR 7". AMSAT. 6 April 2006. http://www.amsat.org/amsat-new/satellites/satInfo.php?satID=9. Retrieved 1 March 2008.
- ^ "AMSAT-OSCAR 7 Satellite Summary". AMSAT. 31 May 2003. http://www.amsat.org/amsat-new/satellites/sat_summary/ao7.php. Retrieved 16 December 2009.
- ^ "Intersatellite communication using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 radio amateur satellites". IEEE. October 1975. http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1451918. Retrieved 16 December 2009.
- ^ Carr, David; Bruninga, Bob (16 February 2011). "OSCAR Satellite Status page by KD5QGR". http://oscar.dcarr.org/. Retrieved 16 February 2011.
Categories:- Artificial satellites orbiting Earth
- Amateur radio satellites
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