Command & Data Handling (C&DH)
The command and data handling subsystem is the brains of the satellite, controlling what the spacecraft does, when it does it, and why it is doing it. It is responsible for data operations and issuing commands to multiple systems aboard the spacecraft. It also controls the decision making capabilities of the spacecraft, as all data that are needed for any function of the satellite pass through this system. Without a command and data handling subsystem, the spacecraft would not function at all.
In order to communicate with all of the various circuit boards and sensors on the MR & MRS SAT spacecraft, the Command and Data Handling system makes use of multiple data buses. On MRS SAT, the central computer communicates over two UART data buses. On MR SAT, the flight computer conducts most communication through an I2C bus. Some sensors on MR SAT require specific forms of communication; the IMU is connected to the flight computer via an SPI bus, and the Imaging Computer is connected to the flight computer with an ethernet cable. Thermal sensors are connected directly to the flight computer with a 1-Wire bus. The Command and Data Handling system is able to issue commands and receive data to and from each system using a variety of data buses.