Satellite Engineering
Understand the spacecraft as one connected system.
Eight subsystems. One mission.
Select a subsystem to see what it does, what it depends on and what it reports.
Mission & Orbit
- Purpose
- Defines what the spacecraft must do and the environment it works in: altitude, inclination, eclipses and ground access.
- Depends on
- Sets the power, thermal and communications budgets for every other subsystem.
- Telemetry
- Position and velocity, eclipse state, β angle.
- Research question
- How does seasonal eclipse duration change the energy margin?
Power
- Purpose
- Generates, stores, regulates and distributes electrical power through the solar arrays, EPS and battery.
- Depends on
- Feeds every subsystem through switched, current-limited power rails.
- Telemetry
- Array voltage and current, battery voltage, current, temperature and SOC, bus voltages, per-channel load current.
- Research question
- How should loads be prioritised during low-energy conditions?
Avionics
- Purpose
- The onboard computer: command and data handling, scheduling and fault management.
- Depends on
- Talks to sensors and actuators over data buses; can power-cycle subsystems through the EPS.
- Telemetry
- Processor load, resets and watchdog events, memory errors, storage use.
- Research question
- How can onboard logic tell a failed sensor from a failing subsystem?
ADCS
- Purpose
- Determines and controls attitude so arrays face the Sun, the payload sees its target and antennas reach the ground.
- Depends on
- Draws power for wheels and magnetorquers; sets pointing for payload and arrays.
- Telemetry
- Attitude quaternion, body rates, wheel speeds, sun-sensor and magnetometer readings.
- Research question
- Which pointing strategy maximises energy without compromising the payload?
Communications
- Purpose
- Downlinks telemetry and payload data and receives commands.
- Depends on
- Links to the ground segment; the transmitter is a major load during passes.
- Telemetry
- Signal strength, link margin, packet counts, transmitter temperature and power.
- Research question
- How should downlink scheduling trade data volume against energy?
Payload
- Purpose
- The mission instrument. For the reference mission, an Earth-observation imager.
- Depends on
- Shapes the power and thermal budgets, ADCS pointing, storage and downlink.
- Telemetry
- Operating mode, temperature, data volume generated.
- Research question
- How much payload duty cycle can the energy budget sustain across seasons?
Thermal
- Purpose
- Keeps components, especially batteries, within limits using coatings, insulation and heaters.
- Depends on
- Heaters draw power; every subsystem has temperature limits.
- Telemetry
- Thermistor temperatures, heater states.
- Research question
- How much energy do battery heaters use in long eclipses, and how can it be reduced?
Ground
- Purpose
- Operates the spacecraft: tracking, commanding, receiving and analysing telemetry.
- Depends on
- Reaches the spacecraft through the communications link; operations decisions feed back on board.
- Telemetry
- Pass schedule, received frames, anomaly logs.
- Research question
- How can routine telemetry reveal early battery degradation?
Go deeper.
Learn Satellite Engineering from spacecraft architecture and mission requirements through subsystem design, verification and engineering reviews. The complete reference and the interactive model are hosted on EV.ENGINEER™.