UoSAT-2

The satellite was the second in the UoSAT series of satellites built by University of Surrey; preceded by UoSAT-1 and followed by UoSAT-3.

The satellite carries a Digitalker speech synthesiser,{{cite magazine|title=Last-Minute Satellite Turns 20|url=https://www.wired.com/science/discoveries/news/2004/03/62471|url-status=dead|archive-url=https://web.archive.org/web/20080626074323/https://www.wired.com/science/discoveries/news/2004/03/62471/|archive-date=26 June 2008|magazine=Wired|publisher=Condé Nast Publications|date=2 March 2004|access-date=26 April 2009}} magnetometers, a CCD camera, a Geiger-Müller tube, and a microphone to detect the vibrations of micrometeoroid impacts. Like UoSAT-1 it transmits telemetry data on the VHF beacon at 1200 baud, using asynchronous AFSK,{{cite web |url=http://www.amsat.org/amsat-new/satellites/sat_summary/uo11.php |url-status=dead|archive-url=https://web.archive.org/web/20041013132019/http://www.amsat.org/amsat-new/satellites/sat_summary/uo11.php|archive-date=13 October 2004|title=Amateur Satellite Summary - UoSAT-OSCAR-11 |author= |website=AMSAT}} though now all analogue telemetry channels have failed; on an FM receiver the audio signal resembles the cassette data format of the contemporary BBC Micro computer.{{cite journal |last=Cook |first=Mike |date=June 1986 |title=Way into the world of satellite telemetry: Mike Cook reviews the Astrid telemetry package |journal=The Micro User |volume=4 |issue=4 |pages=152 |publisher=Database Publications |location=Stockport, UK |issn=0265-4040}} Actually it is a BASICODE signal, but no citation. Slight modulation had also been observed on the S band beacon.{{cite web|url=http://www.users.zetnet.co.uk/clivew/oscar11.htm|title=OSCAR-11 Satellite|access-date=23 February 2008|last=Wallis|first=Clive|date=26 January 2008}}

UoSAT-2's solar arrays were bought at a premium compared to those of UoSAT-1, the design having been space tested by its predecessor.

The British affiliate of AMSAT distributed a library of software for the BBC Micro to track UoSAT-2 and other satellites and analyse telemetry broadcasts. A commercial fixed-frequency receiver, Astrid, was also produced by British firm MM Microwave{{cite web|title=Even More FAQs|last=Webb|first=Stephen R.|url=http://www.g3tpw.co.uk/Page8EvenMoreFAQs.html|date=16 January 2008 |access-date=13 October 2010|archive-url=https://web.archive.org/web/20090802162736/http://www.g3tpw.co.uk/Page8EvenMoreFAQs.html|archive-date=2 August 2009|url-status=dead}} for the education market, with accompanying BBC Micro software to display raw telemetry frames. For versatility the Astrid set included a demodulator to load signals through the serial port of any computer.

File:UoSAT upsets.jpg

As it went around the Earth it encountered data upsets, geo-located around the South Atlantic anomaly.

According to a February 2008 status report the satellite had no viable battery backup, operating only from its solar panels, and a watchdog timer on board was suspending activity for up to three weeks following any power anomaly. At the time of the report it was experiencing continuous sunlight for the last time, with the prediction that "permanent eclipses" in its orbit would begin in the middle of March 2008, limiting transmissions to "a short time, possibly less [than] a single orbit, every 21 days."{{cite web|url=http://www.users.zetnet.co.uk/clivew/2008news.zip|format=Zip|title=OSCAR-11 Report: 2008-02|access-date=2 August 2020|last=Wallis|first=Clive|date=17 February 2008|publisher=AMSAT-UK}} By April 2008 the updated prediction was that eclipses would continue until 2019.{{cite web|first=Clive|last=Wallis|title=Final Monthly OSCAR-11 Report|url=http://www.users.zetnet.co.uk/clivew/u2rpt.htm|date=21 April 2008|access-date=24 April 2009}}

After a 21-month gap in observations, UoSAT-2 resumed sending telemetry sometime before 10 December 2009, and is apparently continuing the watchdog-controlled transmission regime, though now on a ten-days-on, ten-days-off schedule. Its condition has not otherwise improved apart from some recovery of battery power, allowing broadcasts to continue into each eclipse.{{cite web|url=http://www.g3cwv.co.uk/u2rpt.htm|title=Current OSCAR-11 report|last=Wallis|first=Clive|date=30 September 2010|access-date=13 October 2010|url-status=dead|archive-url=https://web.archive.org/web/20140401131737/http://www.g3cwv.co.uk/u2rpt.htm|archive-date=1 April 2014}}

Current observation reports for UoSAT-2 can be viewed and logged at the Oscar Satellite Status Page.{{cite web |title=AMSAT OSCAR Satellite Status |url=https://www.amsat.org/status/ |website=www.amsat.org |access-date=14 December 2023}}

The satellite was instrumental in providing a communications link, known as Nordski Comm, from the Ski-Trek support teams to the expedition party. The position of the skiers' emergency beacon was calculated daily by Cospas-Sarsat ground stations and relayed to them, and thousands of amateur radio listeners, as a spoken message from the Digitalker on board UoSAT-2. The message could also serve as an emergency channel to the skiers in the event that all other radio links failed.{{cite web |last=Meerman |first=Michael |title=Trip to the North Pole: Ski-Trek and NordSki-Comm |date=May 1988 |url=http://www.meerman.fsnet.co.uk/NorthPole/index.html |archive-url=https://web.archive.org/web/20030714130634/http://www.meerman.fsnet.co.uk/NorthPole/index.html |archive-date=14 July 2003}}

{{Reflist}}

{{Portal|Spaceflight}}

• [http://www.uk.amsat.org/ AMSAT-UK]
• [http://www.ee.surrey.ac.uk/Personal/L.Wood/UoSAT-2/ Twenty years in space...] the UoSAT-2 launch video
• [http://www.dd1us.de/spacesounds%202.html Homepage DD1US / Sounds from Space] – Recordings of UO-11 speech and telemetry

{{UoSAT}}

{{OSCAR satellites}}

{{Orbital launches in 1984}}

Category:University of Surrey

Category:Satellites orbiting Earth

Category:Amateur radio satellites

Category:Satellites of the United Kingdom

Category:Spacecraft launched in 1984