The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

stage instead of a Castor 120 motor. The standard Taurus
uses a Castor 120 first stage and a slightly larger Orion
50S-G second stage. The Taurus XL uses the Pegasus XL
rocket motors and is considered a development stage
launch vehicle. The largest Taurus variant, the Taurus
XLS, is a study phase vehicle that adds two Castor IVB
solid rocket boosters to the Taurus XL to increase payload
capacity by 40% over the standard Taurus. For all
Taurus configurations, satellite delivery to a geostationary
transfer orbit can be achieved with the addition of a
Star 37FM perigee kick motor. Five consecutive launch
successes for Taurus, from 1994 through 2000, were followed
by a failure on September 21, 2001, in which the
OrbView-4 and QuikTOMS satellites were lost.
TDRSS (Tracking and Data Relay Satellite System)
A constellation of geosychronous communications satellites
and ground support facilities for use by the Space
Shuttle and other low-Earth-orbiting spacecraft. When
first launched, the TDRS satellites were the largest, most
sophisticated communications satellites ever built. The
second vehicle in the series was lost in the Challenger
disaster and later replaced by TDRS-7. TDRS-8 (H),
-9 (I), and -J are higher performance replacements for the
original satellites. (See table, “TDRS Series.”)
Launch site: Cape Canaveral
Maximum diameter: 3.4 m (stowed), 21 × 13 m (solar
panels and antennas deployed)
Mass (TDRS-8 through -J, on-orbit): 1,781 kg
Teledesic
A communications system designed to provide broadband
and Internet access, videoconferencing, and high-
TDRS Series
Telstar 429
quality voice and other digital data services through a
constellation of 288 satellites in low Earth obit. The
Teledesic network consists of terminals that interface
between the satellite network and terrestrial end-users,
network gateways, network operations and control systems
that perform network management functions, and a
space segment that provides the communication links
and switching among terminals. Teledesic’s space-based
network uses fast-packet switching to provide seamless,
global coverage. Each satellite is a node in the fast-packetswitch
network and communicates through crosslinks to
other satellites in the same and adjacent orbital planes.
Communications are treated within the network as
streams of short, fixed-length packets. Each packet carries
the network address of the destination terminal, and each
node independently selects the least-delay route to that
destination. The Teledesic Network is planned to begin
operations in 2003. Teledesic 1, the first satellite in the
constellation, was launched on February 26, 1998, by a
Pegasus XL from Vandenberg Air Force Base.
telemetry
Data received electronically from a spacecraft during
flight. Telemetry informs ground control about the condition
of the crew and of various critical parts and functions
of the spacecraft.
Telstar
A global network of communications satellites operated
by AT&T Skynet, later Loral Skynet. Telstar 1 was the first
commercial communications satellite; owned by AT&T
and flown by NASA, it relayed the first transatlantic television
transmissions between Andover, Maine, and stations
in Goonhilly, England, and Pleumeur-Bodou,
France. Telstar 8 was scheduled for launch in the third
Spacecraft Date
Launch
Vehicle GSO Location
TDRS-1 Apr. 4, 1983 Shuttle STS-6 49° W
TDRS-3 Sep. 29, 1988 Shuttle STS-26 275° W
TDRS-4 Mar. 13, 1989 Shuttle STS-29 41° W
TDRS-5 Aug. 2, 1991 Shuttle STS-43 174° W
TDRS-6 Jan. 13, 1993 Shuttle STS-54 47° W
TDRS-7 Jul. 4, 1995 Shuttle STS-70 71° W
TDRS-8 (H) Jun. 30, 2000 Atlas IIA 150° W
TDRS-9 (I) Mar. 8, 2002 Atlas IIA n/a*
*A problem with the satellite’s propellant supply after launch left it unclear, as of mid-
2002, whether TRDS-9 could be raised to its intended orbit.