SAiSAT a journey into tomorrow

The Southern Africa Amateur Radio Satellite Association  (SA AMSAT)  has launched  an innovative satellite project and is inviting the participation of South African Universities  and Universities of Technology in the development and construction of a  completely South African Amateur Radio experimental satellite. The objective of this satellite is to demonstrate South Africa’s ability to engineer a satellite, employing the latest technology, and new innovations. In addition there are some feasibility projects for future commercial use.

The name SAiSAT has been taken from the name imagination satellite, which was an earlier project to promote the concept of a South African Amateur Radio Satellite. This initiative resulted in two satellite projects, a basic CubeSat called “Kletskous”, the Afrikaans for chatterbox and SAiSAT.  Kletskous is a shorter term project aimed for launch in 2012/3 while SAiSAT is a very involved project testing the limits of ingenuity and technology.

SAiSAT is based on the CubeSat satellite. The original CubeSat concept came about through a partnership between the California Polytechnique University in San Luis Obispo and Stanford University in Palo Alto, USA. Engineers at the two universities set out to develop a standardised space platform for academic satellite projects. It has since grown to become an international partnership of over 40 institutes that are developing Pico satellites containing scientific and amateur radio communication payloads.

With many institutions participating in the CubeSat programme, the educational benefits are extensive. Students, through hands-on work, are given the opportunity to develop the necessary skills and experience needed to succeed in industry after graduation. The CubeSat programme also benefits private firms and government by providing a low-cost way of flying payloads in space all while creating important educational opportunities for future leaders of industry. This concept was clearly illustrated by the University of Stellenbosch SunSat  success story that qualified Engineers who were snapped up by Industry and resulted in the formation of the company SunSpace.

The late Prof Garth Milne and one of his students who worked on SunSat, South Africa's first satellite

A standard CubeSat is a 10 cm cube with a mass of up to 1 kg. In recent times larger Pico satellites have been developed which are 2 or 3 CubeSat stacked on top of each other, referred as 2U and 3U CubeSats.   

The reason for the decision to go the CubeSat route has only one dimension - financial. Launch opportunities are available at reasonable cost. However going the CubeSat route has restrictions including a very low power budget, very little space ~ 100mm square inside the cube, low mass specification, and the lack of opportunity for a platform stabilisation system. 

SAiSAT overcomes these problems while still complying with the mechanical specification of the CubeSat taking advantage of available launch opportunities and still support many projects on board.

SAiSAT will use fold out panels, a total of 24 in all, that support solar panel steering in order to capture the maximum energy available from the sun. The rear of the solar panels is free for project use. Potentially 24 projects depending on size can be accommodated. In addition the centre core of the Cube is still available for a large battery component. The power budget is to be evaluated but seems to indicate that a 12V DC 16 Ah supply can be accommodated which is very considerable for a small satellite. 

It is further proposed that the outer rim of each panel is fitted with PCB tracks in the form of a coil. The fitted coils will have 4 main functions.

1. To generate additional power from the Earth’s magnetic field.

2. To torque stabilise the satellite against the Earths magnetic field.

3. To give orientation data to resolve the attitude of the satellite.

4. Take additional unused power from the batteries and elevate the satellite into an every increasing orbit thus extending its usefulness and life.