NASA's Tracking and Data Relay Satellites (TDRS)
	National Space Science Data Center NASA Goddard Space Flight Center Greenbelt, MD 20771, USA

The Tracking and Data Relay Satellites (TDRS) comprise the communication satellite component of the Tracking and Data Relay Satellite System (TDRSS). TDRSS is a communication signal relay system which provides tracking and data aquisition services between low earth orbiting spacecraft and control and/or data processing facilities. The system is capable of transmitting to and receiving data from spacecraft over at least 85% of the spacecraft's orbit.

The TDRSS space segment consists of six on-orbit Tracking and Data Relay Satellites located in geosynchronous orbit. Three TDRSs are available for operational support at any given time. The operational spacecraft are located at 41, 174 and 275 degrees west longitude. The other TDRSs in the constellation provide ready backup in the event of a failure to an operational spacecraft and, in some specialized cases, resources for target of opportunity activities.

The TDRSS ground segment is located near Las Cruces, New Mexico, known as the White Sands Complex. Forward data is uplinked from the ground segment to the TDRS and from the TDRS to the spacecraft. Return data is downlinked from the spacecraft via the TDRS to the ground segment and then on to the designated data collection location.

TDRS-A
TDRS-B
TDRS-C
TDRS-D
TDRS-E
TDRS-F
TDRS-G
TDRS-H

Other Sources of TDRS Information/Data

Questions or feedback about this page? Please contact: Dr. Edwin V. Bell, II, ed.bell@gsfc.nasa.gov, +301-286-1187 National Space Science Data Center Code 633, NASA/Goddard Space Flight Center Greenbelt, MD 20771 USA

NASA Official: Mr. Donald Sawyer, Acting Head, NSSDC
Version 2.1, 06 February 2001