Implement the security design principle of clear abstractions.
Attacks on critical software subsystems
Attitude Determination and Control (AD&C) subsystem determines and controls the orientation of the satellite. Any cyberattack that could disrupt some portion of the control loop - sensor data, computation of control commands, and receipt of the commands would impact operations
Telemetry, Tracking and Commanding (TT&C) subsystem provides interface between satellite and ground system. Computations occur within the RF portion of the TT&C subsystem, presenting cyberattack vector
Command and Data Handling (C&DH) subsystem is the brains of the satellite. It interfaces with other subsystems, the payload, and the ground. It receives, validate, decodes, and sends commands to other subsystems, and it receives, processes, formats, and routes data for both the ground and onboard computer. C&DH has the most cyber content and is likely the biggest target for cyberattack.
Electrical Power Subsystem (EPS) provides, stores, distributes, and controls power on the satellite. An attack on EPS could disrupt, damage, or destroy the satellite.