The CCT (Command, Control & Telemetry) Board is one of the circuit boards being designed and made by a number of members of the AMSAT-UK FUNcube development team. Its function is to control what the satellite does in realtime, for example.
- Automatically switch the satellite from ‘education mode’ to ‘amateur mode’.
- Gather readings from more than 30 sensors on the satellite, eg temperatures, battery voltages, currents etc, and convert them ready for down linking via the beacon transmitter.
- Collect and store the data from the Material Science Experiment for a whole orbit to demonstrate variations in thermal performance of material having different surface finishes when in a vacuum.
- Monitor the main battery voltage, and switch the satellite into a low power mode if the battery voltage drops below a certain preset level.
- The board will also contain the vital circuitry to deploy the 2 metre and 70cm antennas after the satellite is deployed from the rocket.
- It will process the readings from the various sensors, and apply Forward Error Correction (FEC) so that stations receiving the telemetry on the ground can do so error free.
- The board communicates with the rest of the satellite via a system known as an I2C bus.
The pictures on this page are of the very first prototype board to be produced. It was not then fully populated with components and there have been several iterations of the PCB since!
The large array on 4 rows of pads on the boards are for a PC104 type connector, which forms the main signalling and power bus in the satellite.
The board contains a low power microprocessor, but it is not planned that this will be reprogrammable after launch, so there will be considerable pressure on the code writers to get the software bug free!
The board has been designed to be very low power, and when not needed, the microprocessor can switch itself to a power saving mode.