NASA communications relay craft rides Atlas into space
BY JUSTIN RAY
Posted: December 4, 2002
After a nine-hour countdown, the rocket's liquid-fueled engines fired to life right on schedule at 9:42 p.m. EST, powering the 415,000-pound, 156-foot tall Atlas slowly off Cape Canaveral Air Force Station's launch pad 36A.
A half-hour later over Africa, the Tracking and Data Relay Satellite-J, or TDRS-J, was released into geosynchronous transfer orbit from the Centaur upper stage. It capped the 23rd and last Atlas 2A rocket launch, ending a 10-year history with a flawless record. Wednesday's flight also extended the Atlas consecutive mission success string to 63.
"We couldn't be more pleased with this evening's launch," said Robert Jenkens Jr., NASA's TDRS project manager from Goddard Space Flight Center. "Controllers have already made contact with TDRS-J and all seems well. My congratulations to everyone who helped make this launch a success."
Over the next eight days, the Boeing-built TDRS-J satellite will perform a series of orbit raising maneuvers with its liquid-fueled kick engine to reach geostationary orbit 22,300 miles above the equator. The craft will match Earth's rotation at 150 degrees West longitude, deploy its appendages and undergo an extensive examination period.
The TDRS system receives voice, television and data transmissions from orbiting space shuttles, the International Space Station and various other satellites and relays the information to Earth. The satellites also work in reverse, allowing ground teams to send signals to their spacecraft via TDRS.
The first TDRS satellite was launched by space shuttle Challenger in April 1983. There were seven original TDRS spacecraft built by TRW and launched on shuttles, one of which was lost in the 1986 explosion of Challenger.
Beginning in 2000, NASA began launching three replenishment craft made by Boeing -- the TDRS-H, -I and -J satellite series -- to keep the space agency's preeminent communications relay system functioning until 2012, while also increasing its capabilities.
"The TDRS spacecraft are the lifeline of mankind in space, and TDRS-J will add significant new capability to the TDRS fleet," said Randy Brinkley, president of Boeing Satellite Systems. "Along with TDRS-H and TDRS-I, this new spacecraft will help maintain and expand the specialized space communications capabilities of the TDRS constellation, which has served numerous national and international missions since 1983."
TDRS-H did suffer an antenna design flaw that reduces some of its performance. Boeing fixed the problem and the TDRS-I satellite, launched this past March, has shown no signs of problems during in-space testing.
TDRS-I experienced its own setback shortly after launch when one of two onboard fuel tanks wouldn't pressurized due to either a faulty valve or a valve wiring error. After several months of recovery efforts, TDRS-I finally made it geostationary orbit. Extra pre-launch testing gave officials confidence TDRS-J wouldn't be hit with such a glitch.
The company retired the Atlas 2A, the least powerful configuration in today's Atlas fleet, in favor of other versions that can loft heavier cargos.
The Atlas 2 family will live on for five more flights of the Atlas 2AS vehicle that sports strap-on solid rocket boosters. The future of the venerable American launcher family is with the Atlas 3 and Atlas 5.
The next Atlas mission is scheduled for early February when an Atlas 3 will loft the AsiaSat 4 commercial communications satellite.
Flight data file
Vehicle: Atlas 2A (AC-144)
Launch date: December 4, 2002
Launch window: 9:42-10:22 p.m. EST (0242-0322 GMT on Dec. 5)
Launch site: SLC-36A, Cape Canaveral AFS, Fla.
Satellite broadcast: GE-2, Trans. 9, C-band
Launch timeline - Chart with times and descriptions of events to occur during the launch.
Ground track - See the trajectory the rocket will follow during its flight.
Atlas 2A vehicle data - Overview of the rocket to be used in this launch.
TDRS-J - Description of this NASA tracking and data relay satellite.
History of TDRSS - Past launches of TDRS satellites and their current status.
Atlas index - A directory of our previous Atlas launch coverage.
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