This is a picture of NASA's UARS satellite. Flickr/NASA Goddard Photo and Video Last year Air Force ground controllers rescued a $1.7 billion military communications satellite that had been stranded in the wrong orbit and at risk of blowing up, as reported by The Washington Post.

The Advanced Extremely High Frequency (AEHF) satellite— the first of six in a $14 billion system designed to give the military more communications capacity and resist signals jamming— sat in a "parking orbit" 31,000 miles above the Earth after ground controllers were unable to fire its main engine to send it into the planned orbit of 22,000 miles above the Earth.

The likely culprit? A piece of cloth blocking the fuel line left there during manufacturing to keep out impurities when the line was disconnected for repair.

The satellite was useless where it was stranded and there was a danger that the fuel backed up in the lines might ignite and explode.

So they devised a rescue plan using the satellite’s two other propulsion systems, which are weaker than the main engine and designed to make course corrections.

Over 14 months ground crews fired the two backup systems hundreds of times— each time checking with other Air Force teams to make sure AEHF-1 wasn't headed for a collision with any space junk— and propelled the satellite across 21,000 miles of space.

The satellite reached orbit last October, more than a year late, and successfully completed testing on Feb. 29. It is said to have enough fuel to complete its expected 14-year life.

Losing AEHF-1 would have been costly and embarrassing. The program was $250 million over budget and two years behind schedule when AEHF-1 lifted off in August 2010. The failure would have raised more questions in Congress about the military and aerospace industry’s ability to manage multibillion-dollar projects.

It also would have delayed the new satellite system (along with all the technology related to it) and would have prolonged the military’s dependence on the aging Milstar system (which first launched in 1994).