AMSAT-OSCAR 51 or AO-51 is the in-orbit name designation of a now defunct (following battery failure) LEO

amateur radio satellite An amateur radio satellite is an artificial satellite built and used by amateur radio operators. It forms part of the Amateur-satellite service. These satellites use amateur radio frequency allocations to facilitate communication between amate ...

of the

OSCAR Oscar, OSCAR, or The Oscar may refer to: People * Oscar (given name), an Irish- and English-language name also used in other languages; the article includes the names Oskar, Oskari, Oszkár, Óscar, and other forms. * Oscar (Irish mythology), ...

series; formerly known as ECHO, built by

AMSAT AMSAT is a name for amateur radio satellite organizations worldwide, but in particular the Radio Amateur Satellite Corporation (AMSAT) with headquarters at Washington, D.C. AMSAT organizations design, build, arrange launches for, and then opera ...

. It was launched on June 29, 2004 from

Baikonur Cosmodrome The Baikonur Cosmodrome ( kk, Байқоңыр ғарыш айлағы, translit=Baiqoñyr ğaryş ailağy, ; russian: Космодром Байконур, translit=Kosmodrom Baykonur, ) is a spaceport in an area of southern Kazakhstan leased to R ...

, Kazakhstan on a Dnepr (rocket), Dnepr launch vehicle. It is in Sun-synchronous orbit, sun synchronous low Earth orbit. AO-51 contained an Frequency modulation, FM repeater with both 144 MHz (VHF) and 1.2 GHz (L band) Telecommunications link#Uplink, uplinks and 435 MHz (UHF) and 2.4 GHz (S band) Telecommunications link#Downlink, downlinks. It also contained a digital subsystem that transmitted telemetry on 70 cm and provided a complete AMSAT-OSCAR 16, PACSAT Bulletin board system, BBS that could be configured on both V band and S band uplinks. As well, there was a 10-meter Phase-shift keying, PSK uplink. AO-51 had four VHF receivers, two UHF transmitters, six modems, and 56 channels of telemetry. The two UHF transmitters were connected to four phased antennas, yielding right-hand circular polarization for the 435.300 downlink and left-hand circular polarization for the 435.150 downlink. The AO-51 FM satellite was easily workable with an amateur radio VHF dual band hand-held radio, as long as you knew when the satellite's Footprint (satellite), footprint was within reach. Transatlantic contacts had been made without much effort, as long as the satellite was approximately mid-Atlantic so that the edge of the satellites footprint was within reach on either continent. As of May 2011 the satellite faced problems with the battery. By September, a work around for the battery issue was found, bringing the repeater back in use. On November 29, 2011, the AO-51 Command Team announced that AO-51 has ceased transmission and is not responding to commands.

External links

AO-51 Control Team NewsAMSAT news about AMSAT 2006 Space SymposiumHow to Work AO-51 with Your HT

References

{{DEFAULTSORT:Ao-51 Amateur radio satellites Communications satellites in low Earth orbit Spacecraft launched by Dnepr rockets Spacecraft launched in 2004