Page 31 - EngineerIT January 2022

AMATEUR RADIO AND SPACE

SUNSAT had several payloads, with
two of the focus areas on amateur
radio and school science projects. In
addition, SUNSAT carried out two NASA
experiments and an experimental push-
broom imager capable of taking pictures
of earth.

Two projects on SUNSAT were built by
school groups:
• George Campbell Technical High
School (Durban) developed and built a
microphone experiment that monitored
sounds generated by vibration, and the
reaction wheels.
• Rhenish Girls High School in
Stellenbosch developed an experiment
that monitored the effect of radiation
on small electronic components.

The high resolution imager provided
50x50 km coverage, operated in real
time on S band. These images were also able to achieve in a true sun-synchronous orbit. The sun-synchronous design was retained
be stored in the RAM disk and portions for the drifting orbit, to concentrate on communication activities when the sun angle
downloaded at lower speeds (9600 baud) becomes unsuitable for imaging but provides more average solar power.
for capturing by radio amateurs and in Following a first technical integration meeting at Boeing in May 1994, a NASA visit
schools. in July 1994 produced a series of technical milestones that were successfully met. A
launch MOU was signed in July 1996. The originally intended launch date of September
NASA saved the day 1996 slipped on numerous occasions because of delays with the prime payload. Launch
NASA saved the SUNSAT programme by eventually occurred on 23 February 1999.
offering a launch on the US Air Force P91- SUNSAT ceased operation on 19 February 2001 when the last signals were received at
1 Argos Delta II mission if SUNSAT could the Stellenbosch ground station The satellite was operational in orbit for 696, days orbiting
carry a JPL TurboRogue GPS receiver for the earth 10 027 times and having travelled nearly 500 million kilometres.
geodynamic research. Denmark’s Ørsted
magnetic research satellite was already SumbandilaSat another amateur radio success
scheduled as a secondary payload, and SumbandilaSat was launched in 2009 and took a total of 1 128 high resolution, usable
SUNSAT could be carried in the opposite images. The image data was applied in local research and on the Copernicus (previously
sector instead of a balance weight. GMES: Global Monitoring for Environment and Security) programme. The data also
The interaction with Boeing and contributed towards disaster management like flood monitoring in Namibia and fire
NASA has been one of the major learning campaigns in the Kruger National Park. It also recorded timely images of the Fukushima
experiences of the SUNSAT programme. nuclear disaster, as well as the Tuscaloosa tornado in the USA. Not generally known is that
NASA was extremely supportive, but the satellite became the darling of the international amateur radio community because of
realistic and strict on SUNSAT’s launch the successful operation of the amateur radio payload.
integration. This resulted in a smooth final In May 2005, the then-DST (Department of Science and Technology) of the South
integration. African government, commissioned Stellenbosch University and SunSpace to develop
The 857 x 655 km elliptical polar orbit the ZASat pathfinder satellite programme (later renamed SumbandilaSat), a technology
was dictated by science requirements demonstrator in conjunction with the South African industry. SumbandilaSat was
of the Ørsted satellite which was the delivered fifteen months later but only launched from Baikonur, Kazakhstan, on 17
initial secondary payload. The orbit plane September 2009.
drifted an hour earlier every 70 days Prof. Milne ensured that an amateur radio payload was included in the plans. It is sad
and was aligned with the sun in mid-July that he did not live to see his dream become a reality. He passed away after a brave and
1999. The orbital drift made long-term long battle with cancer.
repeated imaging impossible and lowered AMSAT SA was invited to provide a transponder for incorporation in the satellite.
the expected output of SUNSAT to With less than three months to develop and build a 144/435 MHz transponder, it was
demonstrate what the satellite would be an impossible task and in conjunction with SunSpace, it was decided to make use of

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