Here’s a high-level breakdown of general satellite parts and their functions, from core structure to mission-specific payloads. 

1. Structure (Bus / Frame)

• Function: Holds all satellite components together and protects them during launch and space operations
• Includes: Panels, brackets, mounting rails
• Key Requirement: Lightweight, strong, vibration-resistant

2. Power System

Provides and manages electrical power for the entire satellite.

• Solar Panels
  • Generate electricity from sunlight
• Batteries
  • Store power for eclipse periods (when the satellite is in Earth’s shadow)
• Power Management & Distribution (PMAD)
  • Regulates voltage and distributes power safely to all subsystems

3. Thermal Control System

• Function: Keeps components within safe operating temperatures
• Includes:
  • Heaters
  • Radiators
  • Thermal blankets (MLI)
• Why it matters: Extreme hot and cold in space can damage electronics

4. Attitude Determination & Control System (ADCS)

Controls the satellite’s orientation (where it points).

• Sensors:
  • Star trackers
  • Sun sensors
  • Gyroscopes
• Actuators:
  • Reaction wheels
  • Control moment gyros
  • Magnetorquers
• Purpose: Point antennas, cameras, solar arrays, or instruments accurately

5. Propulsion System

• Function: Moves and positions the satellite
• Used for:
  • Orbit insertion
  • Station keeping
  • Collision avoidance
  • De-orbiting at end of life
• Types: Chemical, electric, cold gas

6. Communication System (TT&C + Payload Comms)

• Function: Sends and receives data between satellite and ground stations
• Includes:
  • Antennas
  • Transmitters
  • Receivers
• Handles: Telemetry, tracking, commands, and mission data

7. Command & Data Handling (C&DH)

• Function: The satellite’s “brain”
• Responsibilities:
  • Executes commands
  • Processes data
  • Manages onboard software
• Includes: Onboard computer, data buses, memory

8. Payload

The mission-specific equipment—this is why the satellite exists.

• Examples:
  • Cameras (Earth observation)
  • Communication transponders
  • Scientific instruments
  • Radar or hyperspectral sensors

9. Deployment Mechanisms

• Function: Deploys components once in orbit
• Includes:
  • Solar array drives
  • Antenna deployment systems
• Must be: Highly reliable (often single-use)

10. Radiation Protection

• Function: Protects electronics from space radiation
• Includes:
  • Shielding
  • Radiation-hardened components
• Critical for: Long-duration missions and high-radiation orbits

Together, these core satellite subsystems—structure, power, thermal control, ADCS, propulsion, communications, command and data handling, payload, deployment mechanisms, and radiation protection—work as an integrated system that enables reliable operation in the harsh space environment. Each component plays a critical role, from providing mechanical integrity and power generation to ensuring precise pointing, temperature stability, secure communications, and mission execution. The satellite bus supports and protects the payload, while deployment and radiation mitigation systems ensure long-term performance and survivability. When properly designed and integrated, these subsystems function seamlessly to maximize mission life, performance, and reliability, ultimately determining the success of the satellite’s objectives in orbit.

As the commercial and government space sectors accelerate, ESI Motion remains focused on enabling future satellite technologies, sustainable space operations, and high-reliability spacecraft systems. No matter the orbit, mission profile, or application, ESI Motion is here for your satellite mission—delivering space-rated motion control, satellite battery systems, and power electronics that help spacecraft succeed.

As an industry leader, ESI Motion possesses the know-how, experience, and support to help you achieve your mission goals while ensuring optimal performance and longevity for your equipment. We offer many solutions based on your needs, and timeline with Commercial Off-The-Shelf, Modified and Full Customization Space-Rated Systems!

Contact ESI Motion by calling +1.800.823.3235 or email us at sales@esimotion.com. If you need any technical support, our team is here to help.

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