1. Ground Control AERSP 401A

2. Ground System’s Basic Elements Mission Elements –Control the space segment or handle mission data, and includes: Ground Stations Clocks Operations Centers Facility Elements –Support infrastructure that includes: Physical plant (buildings, utilities, staff) Maintenance

3. Mission Elements Ground station –Point of communication with spacecraft –Includes: Antennas Communication equipment Telemetry, Tracking and Control (TT&C) Data processing and routing Control centers

4. Deep Space Network (DSN) Three sites –Goldstone (California) –Madrid (Spain) –Canberra (Australia) –The DSN includes: 3 70-meter stations, 3 26-meter stations, 9 34-meter antennas.

5. Control Centers SOCC –Spacecraft Operations Control Center –Monitors and commands the spacecraft bus and common systems POCC –Payload Operations Control Center –Analyzes the telemetry and mission data from onboard payload instruments and issues commands to these instruments MCC –Mission Control Center –Plans and operates the the entire space mission

6. Data Flow Space Segment (S/C) Data Users Ground System Spacecraft and Payload Support Data Relay Command Requests Mission Data Command and Tracking Data Telemetry Mission Data

7. Payload Operations Control Center NASA Marshall Space Flight Center, Huntsville Alabama

8. Mission Control Center NASA Johnson Spaceflight Center, Houston Texas

9. Ground System Design Process Establish number and locations of ground stations Establish space-to-ground data rates Determine link budget and power requirements Determine required data handling Establish data handling location Decide location of SOCC, POCC and MCC Determine and select communications links Evaluate complete or partial use of service- provided ground systems Iterate as needed

10. Key Design Considerations How frequently and what duration must the spacecraft communicate with the ground? What is the required data transmission rate? How many data users are there? Do we rent space on a currently existing system or do we build a dedicated system?