Image: AEHF-1 Satellite
U.S. Air Force/AP
This artist rendering provided by the U.S. Air Force, shows the AEHF-1 satellite in orbit above the earth. Air Force ground controllers executed a delicate rescue to save the $1.7 billion military communications satellite that was stranded in the wrong orbit and at risk of blowing up -- all possibly because a piece of cloth had been left in a critical fuel line during manufacture.
updated 3/17/2012 4:47:07 PM ET 2012-03-17T20:47:07

Air Force ground controllers delicately rescued a $1.7 billion military communications satellite last year that had been stranded in the wrong orbit and 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 had to battle gravity and dodge space junk while controllers improvised ways to coax it more than 21,000 miles higher to its planned orbit.

"This rescue effort was definitely a very sophisticated and highly technical masterpiece," said Col. Michael Lakos, chief of the Military Satellite Communications Division at Peterson Air Force Base, Colo.

The Advanced Extremely High Frequency satellite is the first of six in a $14 billion system designed to give the military more communications capacity than its current Milstar system as well as resist signals jamming.

Losing AEHF-1 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, first launched 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. As planned, an Atlas V rocket carried AEHF-1 to an elliptical "parking orbit" ranging from 140 miles to 31,000 miles from Earth.

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.

The Air Force acknowledged a problem in the propulsion system shortly after the 2010 launch but didn't publicly discuss the danger the satellite was in until this year.

"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.

Madden quickly assembled teams of "really big brains" from the Air Force and the aerospace industry — including satellite builder Lockheed Martin — to determine what went wrong. His experts said another attempt to fire the engine might trigger an explosion.

"Their findings probably saved the satellite," Madden said.

They devised a rescue plan using the satellite's two other propulsion systems. Both are weaker than the main engine and were designed to make course corrections, not push the satellite across 21,000 miles of space.

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Over the next 14 months, ground crews fired the two propulsion systems hundreds of times. Each time, they had to check with Air Force teams that monitor satellite orbits to make sure AEHF-1 wasn't headed for a collision with a piece of space junk. 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. No other problems have cropped up, and the Air Force said it has enough fuel to complete its expected 14-year life.

Madden's experts identified the likely culprit for the engine malfunction as a blocked fuel line. A Government Accountability Office report issued last year said the blockage might have been a piece of cloth left there during manufacturing. The Air Force said it could have been put there in the first place to keep out impurities when the line was disconnected for a repair.

Defense analyst Marco Caceres, who tracks rocket and satellite failures as part of his work for the Teal group, an aerospace and defense analysis firm, said he had never heard of such a mistake.

"If I had to find the top 10 strange ones, that one would make my list," said Caceres.

Lockheed Martin, which is expected to build all six AEHF satellites, said the probable cause was a foreign object that got into the system during manufacture. The Air Force reduced Lockheed Martin's potential fees by $15 million because of the mistake. Lockheed Martin's current contract for AEHF is valued at $7.8 billion.

The Air Force said the next two AEHF satellites have been inspected and additional checks have been added to the manufacturing process for the remaining versions. Lockheed Martin and the Air Force say the next satellite is scheduled for launch on April 27.

Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

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  5. Accidental art

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  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
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    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
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    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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