Leon Perlman
South Africa is about to enter the exclusive space satellite club with the launch of an affordable 50kg bar-fridge-sized micro-satellite dubbed SunSat. The locally-designed and built satellite will provide data transfer and remote sensing facilities for the Southern African region. The United States Space Agency, Nasa, is sponsoring the SunSat launch, expected at the end of the year. The R1,5-million SunSat 1 micro-satellite project was conceived in 1989 by Stellenbosch University’s Professor Arnold Schoonwinkel. The idea was to create a pool of expertise within the university community as well as facilitate international co-operation. Nearing completion at the University’s engineering faculty, SunSat 1 is scheduled for launch at the end of the year from the Van Den Berg Air Force base. Nasa will launch the satellite in exchange for use of a portion of the satellite as a laser reflector for calibration of its Global Positioning System tracking facility. The project, which is being sponsored by Grinaker Electronics, Plessey Tellumat, Altech and Siemens, has mostly South African designed and manufactured components on board, and has up to 35 students actively involved in assembly and testing. Some 15 masters students, led by Computer and Control System lecturers, began detailed design in 1992 and most prototype hardware was operating by July 1993. According to the SunSat 1 project leader, Professor Garth Milne, the satellite’s `payload’ will consist of an amateur radio transmission facility that supports worldwide activity, a high resolution, three colour CCD stereo still camera capable of resolving images at a resolution of 20m, NiCad batteries, a PAL I video camera, UHF , VHF, S Band and L Band transmitters, a horizon meter, a data storage and retrieval system, on-board telemetry and computing systems and a magnetometer. The design includes backup systems to ensure a fair amount of hardware redundancy. This includes a tele-command system for rebooting the satellite in case of failure of any of the on-board hardware systems. Although SunSat 1 is designed according to Ariane ASAP (Ariane Structure for Auxiliary Payload) specs of 50kg mass and 45cm cube size, it is actually scheduled for launch aboard a Nasa McDonnell Douglas Delta II rocket on a US Air Force mission. It will hover in Low Earth Orbit.
The satellite’s casing, constructed by the university’s Mechanical Engineering department, is made up of layered aluminium modules slotted on top of one another. The CCD camera optics will be supplied by the Council for Scientific and Industrial Research, while the magnetometer will be built by the Hermanus Magnetic institute. To save costs, the satellite will not have any jet propulsion
Although its footprint will only be over Southern Africa for 10 minutes a day, the cube-shaped SunSat 1 will be able to provide stereo colour video images of the region’s cultivated fields, natural vegetation and pollution. Already, says Milne, a commercial version of SunSat 1 is being planned. Images captured in space will be sold commercially as cheaper competition to those provided by the French SPOT satellite. Know-how developed from the program is being exported. The CCD video imager, for example, will be installed in a South Korean satellite, Kit Sat 3, to be launched by the Chinese. Milne sees SunSat 1 as proof that South Africa has the capacity to create a sophisticated micro-satellite manufacturing industry that is able to build custom satellites at a fraction of the price — about R6-million less a micro-satellite — compared to established satellite manufacturers such as Hughes.