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The Tracking and Data Relay Satellite constellation is a space-based communication system used to provide Tracking, Telemetry, Command, and high bandwidth data return services to its many customers. A major component of the system is the spacecraft itself, the Tracking and Data Relay Satellites (TDRS). Aboard each spacecraft are multiple antennae that simultaneously relay signals between the ground and multiple satellites. As a result, TDRS provides a wide variety of services to meet customers' needs and demands.

The primary payload of each TDRS is the microwave communications equipment, two gimbaled antennae and a phased array antenna. The gimbaled antennae provide forward (to the customer satellite), return (from the customer satellite), and tracking services to one customer at a time. Each TDRS communicates with customers at S-band and Ku-band microwave frequencies at various data rates. Through Ka-Band, the 2nd and 3rd generation satellites are able to provide improved overall service potental with substantially higher bandwidth communications services. The phased array antenna provides low-rate S-band forward, return, and tracking services to multiple customers simultaneously. The TDRS Payload is designed to communicate through both gimbaled antennae and the phased array antenna simultaneously to customer electronic communication hardware operating at different carrier frequencies and various data-rates.

The twelfth Tracking and Data Relay Satellite to be launched, it is the second third-generation spacecraft. TDRS-L was constructed by Boeing Space and Intelligence Systems, and is based on the BSS-601HP satellite bus. Fully fuelled, it has a mass of 3,454 kilograms (7,610 lb), and is expected to operate for 15 years. It carries two steerable antennae capable of providing S, Ku and Ka band communications for other spacecraft, plus an array of additional S-band transponders to allow communications at a lower data rate with greater numbers of spacecraft.

Alternate Names

  • 39504
  • TDRS 12
  • Tracking and Data Relay Satellite 12

Facts in Brief

Launch Date: 2014-01-24
Launch Vehicle: Atlas V
Launch Site: Cape Canaveral, United States
Mass: 3454 kg
Nominal Power: 3500 W

Funding Agency

  • NASA-Space Communications and Navigation Office (United States)


  • Communications

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office

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