An artist's concept of TDRS-I. Photo: Boeing

NASA's Tracking and Data Relay Satellite-I has finally reached its orbital perch 22,300 miles above Earth after Boeing's successful attempt to salvage the craft that was crippled by a propulsion system problem.

TDRS-I is the second of three next-generation spacecraft built by Boeing Satellite Systems for NASA to keep the space agency's primary space communications relay network working for years to come.

But shortly after its March 8 launch into a planned preliminary orbit aboard a Lockheed Martin Atlas 2A rocket from Cape Canaveral, ground controllers uncovered a blocked valve inside the satellite that meant one of the two onboard propellant tanks couldn't be pressurized to feed the craft's maneuvering engine. Without the fuel, TDRS-I would not be able to boost itself into geostationary orbit, effectively becoming space junk.

In what Boeing calls a "remote control coronary bypass" procedure, controllers rerouted fuel tank pressurant around the blocked valve and conducted a series of engine burns over the past four months to raise TDRS-I's orbit to 22,300 miles. The last burn was performed early Monday morning.

"The TDRS-I recovery effort was an incredible feat that demonstrates the inherent design robustness of our products and the incredible space operation knowledge and experience of our team," said Randy Brinkley, president of Boeing Satellite Systems. "I am so very proud of our TDRS-I team and the support and confidence our NASA customer has shown during this challenging period. All of us at BSS recognized how critical TDRS-I is to NASA's Space Shuttle and International Space Station and I am inspired by our joint team's efforts.

"We could not have accomplished this recovery without a joint effort. NASA co-located their personnel in our Mission Control Center in El Segundo, and also provided support from their ground station network throughout the recovery effort. The joint effort showed what can be accomplished by working together." "This amazing milestone was achieved through the dedication and extensive personal sacrifices of the Boeing/NASA TDRS-I mission recovery team," said Robert Jenkens Jr., TDRS Project Manager at NASA's Goddard Space Flight Center. "These talented and innovative individuals were able to collectively overcome many significant obstacles along the way," he added.

"Despite what initially appeared to be an impossible challenge, the team was able to achieve a geosynchronous orbit and demonstrate Boeing's commitment to the success of NASA's TDRS-H, -I, -J Program," said Jenkens. "Looking ahead, we now have to complete the appendage-deployment phase and conduct on-orbit testing to evaluate the state of health and performance of the satellite," he said.

The satellite will now deploy its antennas and undergo at least eight weeks of in-orbit testing.

Once the checkout is completed, NASA will take complete ownership of the spacecraft from Boeing, renaming it TDRS-9 for its entry into the TDRS constellation.

Based on the remaining amount of propellant, the satellite is expected to fulfill its contractually required 15-year service life.

Working like switchboards 22,300 miles above the planet, the NASA Tracking and Data Relay satellites receive voice, television and data transmissions from orbiting space shuttles, the International Space Station and various other satellites and relay the information to Earth. The satellites work in reverse, too, allowing ground teams to send signals to their spacecraft via TDRS.

The next satellite in the series, TDRS-J, is scheduled for launch on November 20.