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Note: This article was copied verbatim from the NASA HISTORICAL DATA BOOK, Volume VI numbered NASA SP-2000-4012 by Judy A. Rumerman.

"Tracking and Data Acquisition System Description

From 1979 to 1988, NASA's space tracking and data systems transitioned from a totally ground-based network mode of operation to a system with space-based capabilities for monitoring and commanding low-Earth orbital spacecraft and ground-based capabilities for deep space missions and particular types of low-Earth orbital missions. The following sections describe the Ground Network and the Space Network as they existed from 1979 to 1988.

Ground Network

The NASA Ground Network consisted of the STDN, the DSN, and the Aeronautics, Balloons, and Sounding Rocket Network. From 1979 to 1988, the Ground Network reduced the number of tracking stations while adding to the facilities and increased the capabilities at the remaining stations.

Spaceflight Tracking and Data Network

The STDN was operated, maintained, and controlled by the Networks Division of the Goddard Space Flight Center in Greenbelt, Maryland. It provided tracking, data acquisition, and associated support for low-Earth orbital missions. The network was operated through NASA contracts and interagency and international agreements that provided staffing and logistical support. The Networks Division also operated the Network Control Center and NASA Ground Terminal. The division was responsible for testing, calibrating, and configuring network resources to ensure network support capability before each mission. It coordinated, scheduled, and directed all network activity and provided the necessary interface among Goddard elements and other agencies, centers, and networks.

The STDN was composed of the White Sands Ground Terminal and the NASA Ground Terminal in White Sands, New Mexico; NASCOM, the Flight Dynamics Facility, and the Simulation Operations Center at Goddard; and the ground network. The ground elements were linked by voice and data communications services provided by NASCOM. The prime operational communications data were formatted into 4,800-bit blocks and transmitted on the NASCOM wideband data and message switching system. Other communications traveled by teletype and facsimile facilities. Each ground station in the network provided coverage for approximately 20 percent of a satellite's or spacecraft's orbit and was limited to brief periods when the satellite or spacecraft was within the line of sight of a given tracking station. The various antennas at each STDN site accomplished a specific task, usually in a specific frequency band.

To provide reliable, continuous, and instantaneous communications support to the Space Shuttle, NASA added new sites and upgraded some of its existing facilities and capabilities for the Shuttle test phase and early Shuttle flights. In 1981, new sites for UHF air-to-ground voice were added in Dakar in Senegal, Botswana, and Yarragardee in Australia. Also added were three Shuttle-unique stations in Florida, California, and New Mexico. Department of Defense tracking and telemetry elements also supported the Shuttle flights. The Dakar UHF air-to-ground voice station was upgraded in 1982, before the STS-4 mission, to an S-band telemetry, voice, and command station. The change allowed for continuous telemetry data coverage between Bermuda and Hawaii for all due-east launches beginning with STS-4. This mid-point station allowed for the analysis of initial Orbital Maneuvering System bum data and provided for crew updates in case of an abort.

The network for the Shuttle orbital flight test program (STS-1 through STS-4) consisted of seventeen ground stations equipped with 4.26-,9.14-,12.19-, and 25.9-meter S-band antenna systems and C-band radar systems, NASCOM augmented by fifteen Department of Defense geographical locations providing C-band support, and one Department of Defense 18.3-meter S-band antenna system. In addition, six major computing interfaces-the Network Operations Control Center at Goddard, the Western Space and Missile Center at Vandenberg Air Force Base in California, the Air Force Satellite Control Facility in Sunnyvale, California, the White Sands Missile Range in New Mexico, and the Eastern Space and Missile Center in Florida-provided real-time network computational support. The stations that closed during this period were at Winkfield, England, at Rosman, North Carolina, which was turned over to the Department of Defense at the start of 1981, and at Quito, Ecuador, which closed in 1982 and transferred its equipment to the Dakar station.

The STDN stations were at Ascension Island, Bermuda, *Botswana (beginning with STS-3), Buckhorn (Dryden Flight Research Facility) in California, *Dakar (beginning with STS-3), Fairbanks in Alaska, Goddard Space Flight Center, Goldstone (Ft. Irwin, California), Guam, Kokee in Hawaii, Madrid in Spain, Merritt Island in Florida, Orroral Valley (Canberra, Australia), Ponce de Leon in Florida (added for Shuttle program), Quito (closed in 1982), Santiago in Chile, Seychelles in the Indian Ocean (added for Shuttle program), Tula Peak in New Mexico, Wallops Orbital Tracking Station in Virginia, and Yarragardee (added for Shuttle program). Tula Peak, which initiated operations in 1979, was designated as a tracking support site for Shuttle orbital flight test landing activities. It initially suspended operations following STS-2, because of budget restrictions, but it was forced to reactivate its facilities on very short notice when STS-3 had to land at White Sands, New Mexico, rather than at Edwards Air Force Base in California because of bad weather in California.
* See note concerning Botswana & Dakar.

Several instrumented U.S. Air Force aircraft, referred to as advanced range instrumentation aircraft, also supported the STDN. They were situated on request at various locations around the world where ground stations could not support Space Shuttle missions.

The Merritt Island, Florida, S-band station provided data to the Launch Control Center at Kennedy Space Center and the Mission Control Center at Johnson Space Center during prelaunch testing and terminal countdown. During the first minutes of launch, the Merritt Island and Ponce de Leon, Florida, S-band and Bermuda S-band stations, respectively, provided tracking data, both high speed and low speed, to the control centers at Kennedy and Johnson. The C-band stations located at Bermuda, Wallops Island in Virginia, the Grand Bahamas, Grand Turk, Antigua, and Cape Canaveral and Patrick Air Force Base in Florida also provided tracking data.

The Madrid, Indian Ocean Seychelles, Australian Orroral and Yarragardee, and Guam stations provided critical support to the Orbital Maneuvering System bums. During the orbital phase, all the Sand C-band stations that saw the Space Shuttle orbiter at 30 degrees above the horizon provided appropriate tracking, telemetry, air-ground, and command support to the Johnson Mission Control Center through Goddard.

During the nominal reentry and landing phase planned for Edwards Air Force Base, California, the Goldstone and Buckhorn, California, S-band stations and the C-band stations at the Pacific Missile Test Center, Vandenberg Air Force Base, Edwards Air Force Base; and Dryden Flight Research Center provided tracking, telemetry, command, and air-ground support to the orbiter. These locations also sent appropriate data to the control centers at Johnson and Kennedy. The tracking station at Ponce de Leon Inlet, Florida, provided support for the Space Shuttle during powered flight because of attenuation problems from the solid rocket booster motor plume.

In 1983, after supporting the STS-8 night landing, the Buckhorn special-purpose tracking station at Dryden Flight Research Center in California was phased out and operations terminated. This station had been established to support the Space Shuttle approach and landing tests and the operational flight test landings. Equipment from the Buckhorn site was moved a short distance to the Aeronautical Training Facility at Dryden, which already had been used to support NASA's aeronautics activities. This site was then also used to support STS missions.

When the first Tracking and Data Relay Satellite (TDRS-l) began tracking Shuttle missions in 1984, the White Sands Ground Terminal acquired the ground terminal communications relay equipment for the command, telemetry, tracking, and control equipment of the TDRSS (see the "Space Network" section below). The NASA Ground Terminal was co-located with the White Sands Ground Terminal. The NASA Ground Terminal, in combination with NASCOM, was NASA's physical and electrical interface with theTDRSS. The NASA Ground Terminal provided the interfaces with the common carrier, monitored the quality of the service from the TDRSS, and provided remote data quality to the Network Control Center.

The STDN consolidated its operations as the TDRSS took over the function of tracking most Earth-orbiting satellites. The facilities at Fairbanks, Alaska, were transferred to the National Oceanic and Atmospheric Administration in 1984. The STDN relinquished its Goldstone, Madrid, and Canberra stations and transferred them to the DSN sites. It gave the DSN support responsibility for spacecraft above the view of the TDRSS and for older spacecraft that were incompatible with the TDRSS. If the second TDRS had been successfully placed in orbit in 1986 as planned, the closure of additional STDN tracking stations would have occurred. However, the loss of the spacecraft in the Challenger explosion delayed the TDRS deployment by two years, and the reduction in STDN facilities was put on hold until the launch of TDRS-3 in September 1988.

At the time of the TDRS-3 launch, STDN tracking stations remained at Ascension Island, Bermuda, Canberra, Dakar, Guam, Kauai, Merritt Island, Ponce de Leon, Santiago, and Wallops Flight Facility. After the TDRSS was declared operational in 1989, the STDN decreased to stations at Wallops Island, Bermuda, Merritt Island, Ponce de Leon, and Dakar."

Late Note:
Dakar closed in the mid 90's while Bermuda shutdown in late 2001.

* Click HERE for note concerning Botswana & Daker sites.