SpatialNews Press Release

ADVANCED COMMUNICATIONS SATELLITE TO SPEED UP SPACE-BASED DATA

nmsp.gsfc.nasa.gov/tdrss/tdrsshome.html

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NASA is ready to launch the third advanced Tracking and Data Relay Satellites, named TDRS-J, which will have the ability to transfer data 5,000 times faster than a computer's 56K modem, transmit near real-time audio and high-resolution digital video from Earth-orbiting spacecraft and provide tracking services for expendable launch vehicles.

TDRS-J is scheduled to launch Dec. 4 aboard an Atlas IIA rocket from Cape Canaveral Air Force Station, Fla., at the beginning of a 40-minute launch window, which opens at 9:42 p.m. EST.

The new trio of satellites joins forces with the original TDRS constellation to support the Space Shuttle, International Space Station, Hubble Space Telescope and a host of other Earth-orbiting spacecraft.

"This state-of-the-art communications system will support NASA's mission by providing a communications backbone for astronauts aboard the Shuttle and Space Station, as well as relay vital data from several Earth and space science missions," said Robert Jenkens Jr., TDRS Project Manager at NASA's Goddard Space Flight Center, Greenbelt, Md.

TDRS-J features the following capabilities:

* S-band Single Access: Two 15-foot diameter steerable antennas, used at the 2.0 to 2.3 GHz (gigahertz) band, supply robust communications to user satellites with smaller antennas and receive telemetry from expendable launch vehicles during launch.

* Ku-band Single Access: The same two antennas, operating from 13.7 to 15.0 GHz, provide higher bandwidth for user satellites, provide high-resolution digital television for Space Shuttle video communications and can quickly transfer large volumes of data from tape or solid-state data recorders aboard NASA scientific spacecraft.

* Ka-band Single Access: This new higher-frequency service, which operates from 22.5 to 27.5 Gigahertz and increases data rate capabilities to 800 megabits per second, will provide communications for future missions requiring higher bandwidths such as multi-spectral instruments for Earth science applications.

* Multiple Access: This system is capable of receiving signals from five user spacecraft simultaneously at rates up to 3 megabits per second, while transmitting to a single user at up to 300 kilobits per second. The system operates using a phased-array antenna in the 2.0 to 2.3 GHz range.

For two weeks following the launch, transfer orbit operations will boost the 7,039-pound (3,196-kilogram) satellite into a geosynchronous orbit 22,300 miles above the Earth's equator. Upon completion of on-orbit testing and acceptance, TDRS-J will be renamed TDRS-10.

Fully deployed, the satellite measures approximately 69 feet long (21 meters) by 43 feet (13 meters) wide. The satellite's silicon celled solar arrays will generate 2,300 watts of on-orbit power and a nickel-hydrogen battery will supply power during solar eclipses.

The TDRS replenishment program cost approximately $800 million and includes three satellites, expendable launch vehicles, upgrades to the White Sands Complex in Las Cruces, N.M., and NASA program costs. Boeing Satellite Systems, El Segundo, Calif., designed, built and tested TDRS-H, I and J for NASA under a fixed-price contract.

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