Orbital Sciences
The Galaxy 15 satellite is seen before its 2005 launch to geostationary orbit nearly 36,000 kilometers over the Earth's equator.
By Space News staff writer
updated 1/13/2011 9:48:47 PM ET 2011-01-14T02:48:47

Intelsat’s Galaxy 15 telecommunications satellite, which remained electrically active while adrift in orbit for more than eight months, was rendered unable to take commands by an electrostatic discharge that fouled its onboard software, Intelsat officials said Thursday.

The upset, which occurred last April, forced Intelsat and operators of neighboring satellites to perform orbital maneuvers to avoid frequency interference as Galaxy 15 drifted along the geostationary arc. Intelsat officials say the glitch had nothing to do with solar activity.

In a conference call with reporters, Tobias Nassif, Intelsat vice president for satellite operations and engineering, said a failure review board that includes representatives from Washington- and Luxembourg-based Intelsat; Galaxy 15's builder, Orbital Sciences Corp. of Dulles, Va.; and the Los Angeles-based Aerospace Corp. will likely report its final conclusions about what went wrong sometime in February. But because Intelsat and Orbital were able to recover and regain control of the satellite once it lost its Earth lock and was reset, the possibility of a hardware failure has been eliminated.

The exact cause of the electrostatic discharge may never be known. Similar phenomena affect other satellites in orbit from time to time, although Galaxy 15 is believed to be the first to have reacted the way it did. Intelsat and Orbital have designed three software patches that should prevent a recurrence of the problem on Galaxy 15 or any other Orbital-built satellite that uses the same platform.

The software uploads are mainly designed to ensure that the satellite will respond to commands even if a similar electrostatic discharge occurs, and that its communications payload will automatically shut down if it has not received specific ground commands within a 21-day period.

"We ruled out any activity from the sun as having any impact on Galaxy 15," Nassif said. Industry speculation at the time of the failure was that unusually intense solar activity around April 5 could have triggered the satellite’s failure.

Orbital is also reinforcing components on similar satellites that have yet to be launched.

Intelsat expects Galaxy 15 to arrive at its test position of 93 degrees west around Jan. 15, where it will undergo a full battery of tests before being redeployed as an operational satellite with more than a decade of life remaining, Nassif said.

With Galaxy 15’s C-band payload still active and threatening to interfere with other C-band satellites in its path, Intelsat was obliged to craft flyby procedures that permitted the satellite to wander through other satellite positions without wreaking havoc. Fifteen such maneuvers were conducted in total.

During two of these flybys, Galaxy 15 came to within 0.4 degrees of a neighboring satellite — a feat Nassif said has never been attempted for telecommunications satellites. Despite this proximity, the Intelsat-designed signal rerouting was able to prevent any major disturbance of other satellites’ signals.

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Dianne J. VanBeber, Intelsat vice president for investor relations, said Intelsat has not yet calculated the cost of the Galaxy 15 problem in terms of labor hours and the unplanned use of teleports. But, she said the total is almost certain to be modest — perhaps less than $1 million — during the nearly nine months from the April 5 failure to the satellite’s late-December return to operational control.

Intelsat replaced Galaxy 15 with an in-orbit spare satellite, Galaxy 12, for the company’s C-band customers, who are mainly North American television broadcasters. But Galaxy 15 also carries an L-band navigation payload managed by Lockheed Martin Corp. for the U.S. Federal Aviation Administration (FAA). The payload is one of several aboard geostationary-orbiting satellites that act as an overlay for the U.S. GPS positioning and navigation constellation.

Midway through its orbital drift, Galaxy 15 was no longer in a position to provide the navigation service, and the FAA was unable to provide the expected service for Alaskan air traffic. Nassif said Intelsat expects this navigation service to be resumed once the satellite completes its tests.

This article was provided by Space News, dedicated to covering all aspects of the space industry. Peter B. de Selding is the European correspondent for Space News.

© 2013 Space.com. All rights reserved. More from Space.com.

Photos: Month in Space: January 2014

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  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
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  5. Accidental art

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  6. Supersonic test flight

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