DIY Satellite Platforms

Chapter 5. Programming and Coding

Potentially, your processor can control everything from maneuver and power through to data gathering and transmission. You do have a processor budget—how many operations per second it can run. You also want a bulletproof mission, which suggests as little processing as possible to ensure that your programs are simple, debugged, and only used when needed.

Therefore, I recommend you not use computer commanding of your power system, but rely on good power architecture. Your primary use of the processor is for three purposes: data handling, turning your radio on and off, and commanding any engineering tests.

Data handling

Process and optionally store onboard sensor/project data.

Turning the transmitter on or off

• Receive ground commands telling satellite to broadcast its data to Earth.
• Send data to the transmitter for broadcasting down to Earth.
• Process any turn off now instructions.

Commanding any engineering tests

Only if you have an engineering experiment—such as an ion drive—that you wish to turn on, turn off, or change the operation of during the flight. Most sensors, in contrast, will be “always on,” even if there isn’t bandwidth to transmit.

It is better to have the sensors always on, requiring no ground commanding, and throw away data if you cannot transmit it, than the alternative. The alternative is to use valuable radio time to tell the satellite to do its work. Design your satellite sensors to be always on within your power budget and ...