Structure of Satellites

Communications Satellites are usually composed of the following subsystems:
  • Communication Payload, normally composed of transponders, antenna, and switching systems
  • Engines used to bring the satellite to its desired orbit
  • Station Keeping Tracking and stabilization subsystem used to keep the satellite in the right orbit, with its antennas pointed in the right direction, and its power system pointed towards the sun
  • Power subsystem, used to power the Satellite systems, normally composed of solar cells, and batteries that maintain power during solar eclipse
  • Command and Control subsystem, which maintains communications with ground control stations. The ground control earth stations monitor the satellite performance and control its functionality during various phases of its life-cycle.
The bandwidth available from a satellite depends upon the number of transponders provided by the satellite. Each service (TV, Voice, Internet, radio) requires a different amount of bandwidth for transmission. This is typically known as link budgeting and a network simulator can be used to arrive at the exact value.

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Primary Function: Worldwide, long-haul communications

Primary Contractor: Lockheed Martin Missiles and Space

Weight: 2,716 pounds (1,232 kilograms)


Power Plant: Solar arrays generating average of 1,500 watts

Orbit Altitude: 22,230 miles (35,887 kilometers)

Dimensions: Rectangular body is 6 feet long (1.8 meters), 6 feet high (1.8 meters), and 7 feet wide (2.1 meters); 38-foot span (11.5 meters) with solar arrays deployed

Launch Vehicle: Atlas II, later the evolved                                                           expendable launch vehicle
References:
UNMC Group project, BPA Module, Spring 2104