The primary TDRS ground terminals are located near Las Cruces, New Mexico.  These two functionally identical ground terminals, White Sands Ground Terminal (WSGT) and Second TDRS Ground Terminal (STGT), are collectively known as the White Sands Complex. Customer forward data is uplinked from the ground segment to a TDRS and relayed from the TDRS to the customer spacecraft. Return data is relayed from the customer spacecraft through a TDRS to the WSC ground segment and then on to the customer designated data collection location. The three operational TDRS satelites are located in geosynchronous orbit above three different regions of the Earth. As the user spacecraft moves in its orbit, it will continually move from one TDRS to another.

Currently the TDRS team is working with the Space Network to upgrade the WSC ground system for the new generation of TDRS. This very intense process involves modernized Command and Telemetry systems, new generation Ground Based Beamformers (GBBF), two Ka-Band End-to-End Test Antenna systems, and SGLT upgrades associated with the new TDRS Spacecraft.  During this time, the Space Network remains continually operational with little to no interruption of service for the Space Network's customers.

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Second TDRSS Ground Terminal at Dawn. Credit: W.R. Gardner (NASA)

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The TDRS Project, established in 1973, is responsible for the development, launch, and on-orbit test and calibration of TDRS spacecraft. There have been four procurements of TDRS spacecraft, which include the Basic Program (TDRS F1-F6), the Replacement Program (TDRS F7), the TDRS H,I,J Program, and the TDRS K,L,M Program.  TDRS Flight 7 was a replacement for Flight 2, which was lost aboard Challenger in 1986.  The first seven spacecraft (TDRS F1-F7) are referred to as the First Generation, the H,I,J series are called the Second Generation, and the K,L,M series are known as the Third Generation.  TDRS F1-7 spacecraft were built by TRW (now Northrop Grumman) in Redondo Beach, CA.  The TDRS F8-10 (H,I,J) spacecraft were built by Hughes (now Boeing) in El Segundo, CA. 

The NASA Space Network consists of the on-orbit telecommunications TDRS satellites, placed in geosynchronous orbit, and the associated TDRS ground stations, located in White Sands, New Mexico and Guam. The TDRS constellation is capable of providing nearly continuous high bandwidth (S, Ku, and Ka band) telecommunications services for expandable launch vehicles and user spacecraft in low Earth orbit. Examples include: the Hubble Space Telescope, the Earth Observig Fleet and the International Space Station.  The TDRS System is a basic agency capability and a critical national resource.

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Update: 31.12.2013

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NASA's Tracking and Data Relay Satellite (TDRS)-L will be the focus of a media opportunity at 10 a.m. EST Friday, Jan. 3, at the Astrotech Space Operations facility in Titusville, Fla.

Media  will be able to view the TDRS-L spacecraft and interview project and launch program officials from NASA's Goddard Space Flight Center in Greenbelt, Md.; the Launch Services Program at the agency's Kennedy Space Center in Florida; and United Launch Alliance (ULA).

TDRS-L is scheduled to lift off on a ULA Atlas V 401 rocket from Cape Canaveral Air Force Station in Florida on Jan. 23 at the opening of a 40-minute launch window that extends from 9:05 to 9:45 p.m.

The TDRS-L spacecraft is the second of three next-generation satellites designed to ensure vital operational continuity for NASA by expanding the lifespan of the fleet, which now consists of eight satellites in geostationary orbit. The spacecraft provide tracking, telemetry, command and high bandwidth data return services for numerous science and human exploration missions orbiting Earth. These include NASA's Hubble Space Telescope and the International Space Station. TDRS-L has a high-performance solar panel designed for more spacecraft power to meet the growing S-band communications requirements.

Full clean room attire must be worn during the media opportunity and will be furnished. Journalists should not wear perfume, cologne or makeup. Long pants and closed-toe shoes must be worn. No shorts or skirts will be permitted. Some camera equipment may be identified by Boeing contamination control specialists as having to be cleaned before being taken into the high bay facility. Alcohol wipes will be provided. All camera equipment must be self-contained, and no portable lights are allowed. Flash photography will not be permitted, however, the facility has adequate metal halide lighting for pictures. Wireless microphones also are not permitted inside the high bay.

On Jan. 3, U.S.  media may proceed directly to Astrotech, which is located in the Spaceport Florida Industrial Park, 1515 Chaffee Drive, Titusville. Access will be available starting at 9:45 a.m., and the event will begin at 10 a.m.

Only media who are United States citizens may attend this event, per Astrotech rules. A government-issued photo identification, such as a driver's license or permanently issued NASA media accreditation badge from Kennedy will be acceptable. In addition, proof of U.S. citizenship also is required, such as a passport or birth certificate.

Journalists should call Kennedy's media update phone line at 321-867-2525 on Thursday evening, Jan. 2, to confirm the event still is on schedule.

Boeing Space and Intelligence Systems in El Segundo, Calif., built TDRS-L. NASA's Space Communications and Navigation Program, part of the Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington, is responsible for the TDRS network. NASA's Launch Services Program at Kennedy is responsible for launch management. United Launch Alliance provides the Atlas V rocket and launch service.

Quelle: NASA