DENVER — Air Force ground controllers delicately rescued a $1.7 billion military communications satellite last year that had been stranded in the wrong orbit and was at risk of blowing up — all possibly because a piece of cloth had been left in a critical fuel line during manufacture.
During the 14-month effort, the satellite battled gravity and dodged space junk while controllers improvised ways to coax it more than 21,000 miles to its planned orbit.
The Advanced Extremely High Frequency satellite is the first of six in a $14 billion system designed to give the military more communications capacity.
Losing the satellite would have been a costly and embarrassing blow. It would have delayed the satellite system along with all the related technology that will use it, and it would have prolonged the military’s dependence on the aging Milstar system begun in 1994. It also would have raised more questions in Congress about the military and aerospace industry’s ability to manage multibillion-dollar projects.
The program was $250 million over budget and two years behind schedule when the first satellite, AEHF-1, lifted off from Cape Canaveral, Fla., in August, 2010.
Trouble came days later when ground controllers twice directed AEHF-1 to fire its main engine to begin moving into a circular orbit more than 22,000 miles above the Earth.
Both times the satellite shut the engine down when it detected that it wasn’t working — a safety feature.
AEHF-1 was useless in the parking orbit where it was stranded. Worse, there was a danger the fuel backed up in the lines might ignite and explode, the Air Force said.
“My initial reaction was we had lost the mission,” said Dave Madden, the civilian director of the Military Satellite Communications System Directorate at Los Angeles Air Force Base, Calif.
He assembled teams of “really big brains” from the Air Force and the aerospace industry who said another attempt to fire the engine might trigger an explosion.
They devised a rescue plan using the satellite’s two other propulsion systems. Both were designed to make course corrections, not push the satellite across 21,000 miles of space.
Over the next 14 months, ground crews fired the two propulsion systems hundreds of times. They had to move the satellite out of the way of debris three or four times.
One of the backup propulsion systems required electricity, so the satellite’s solar panels had to be extended earlier than planned. That put them at risk of damage as the satellite passed through radiation belts around the Earth. They survived without damage.
The satellite reached orbit in October, more than a year late, and successfully completed testing on Feb. 29, Lockheed Martin said. The Air Force said it has enough fuel to complete its expected 14-year life.