SA RADIO AMATEURS TO TAKE TECHNOLOGY INTO SPACE 

South African Radio Amateurs are set to join other amateur and university groups in the world to build and launch their own CubeSat. This was announced in a presentation at the recently held SA AMSAT Space Symposium in Durban. 

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 this many institutes 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.

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 2Uand 3U CubeSats.  

A mission with a Mission

The  planned SA AMSAT CubeSat will be  single 10x10cm satellite with two payload objectives. The first objective is a mission with a Mission.  The world has experienced a long solar minimum which means that ionospheric communication had been very limited and for a few years was almost exclusively the domain of  the commercial broadcasters running Megawatts. HF radio communication is very susceptible to noise levels that are created by power lines, electrical installations and overhead lines used by trains and busses and  power line telecommunication systems. If fact today there are many installation that do not necessarily comply with internationally agreed emission standards. With increasing solar activity interference signals are propagated over large areas and will interfere with HF communication. The important mission of the SA AMSAT CubeSat is to measure the High Frequency noise levels over South Africa and report these measurement back to a ground station for analysis and action to reduce these unwanted signals. The information from the tiny satellite will identify the areas where the HF frequency polluters are situated and will help "reducing or eliminating the source. The second payload will be amateur radio related and may include a 30 kHz linear transponder and an Automatic Packet Reporting System (APRS). APRS is a two-way tactical real-time digital communication system capable of sharing information about everything going on in a local area. APRS also supports global callsign-to-callsign messaging.

Another interesting payload  being discussed is to evaluate the feasibility of using the earths magnetic field to facilitate the storage of energy as apposed to a battery. The principle involves rotating a coil (iron less armature) by applying solar cell energy with a current limiting source to the coil. The coil is mounted on suitable bearings such as magnetic bearings and allowed to rotate to high speed. The armature current is electronically switched to embrace the earths magnetic field and force rotation. Spinning at high velocity the armature will store energy. This energy can be obtained by again using the earth’s magnetic field to induce current into the rotating armature coil.

The device will need a discrete rectifier and regulator to make it available for use. Quantity of energy stored referenced to wait, should be far greater than chemical batteries. The very long life time expected, from this device should improve the present power system.