AT&T’s satellite telly service DirecTV will push one of its birds beyond its geostationary orbit – before it has a chance to explode into a million pieces.
The broadcaster fears the batteries on board its Boeing-built Spaceway-1 satellite, which has been aloft since 2005, may detonate, spewing debris into the Clarke Orbit – named after the sci-fi super-author Arthur – and destroying other craft.
Specifically, Spaceway-1 has suffered “irreversible thermal damage to its batteries,” DirecTV explained in a request to America's comms watchdog, the FCC, to change Spaceway-1's orbit. Both the bird's builder and operator are worried that if they attempt to draw power from the batteries, they could explode.
“Boeing, the spacecraft manufacturer, concluded based on all available data that the batteries’ cells cannot be guaranteed to withstand the pressures needed to support safe operation of the spacecraft in eclipse operations; rather, there is a significant risk that these battery cells could burst,” DirecTV said.
When it launched, Spaceway-1 was humankind's chunkiest communications satellite ever to go into orbit, weighing in at 13,400lb or 6,080kg. If it blows up, the debris field would potentially wreck other sats circling 35,786 kilometers (22,236 miles) from Earth.
At the moment there’s nothing to worry about: the satellite is operating under the power from its solar cells alone without involving the batteries. However, it will be eclipsed from the Sun by Earth on February 25, and will need batteries to continue to function, which may make it explode if used, and so DirecTV just wants to ship it out of the Clarke orbit as soon as possible to avoid any fuss.
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Satellites in low-Earth orbit are typically sent back down to our planet when they reach end of life, and are destroyed as they reenter the atmosphere. However, objects as far out as geostationary orbit are pushed the opposite way, put into a parking orbit, and left there for future generations to decide how to deal with the mess.
American outfits, at least, require FCC approval to shove kit further out into the obsidian void, and there are set procedures for such a maneuver, such as retaining just enough fuel to make the journey and dump the rest. In its filing, DirecTV said there isn’t time to vent the remaining 73kg (161lb) of fuel before the February deadline. Shifting it to the graveyard orbit will take 21 days, which leaves only a few days for propellant dumping before the risk of the batteries explosively failing. In other words, it wants to go now, now, now.
The FCC granted [PDF] the application on January 19, and today, DirecTV confirmed [PDF] it will move Spacweay-1 up to 500km from its current orbit, and "will utilize four telemetry, tracking, and control earth stations during drift, including Intelsat License LLC’s Riverside, California Ka-band earth station (call sign E170039) which will provide greater western visibility."
In case you’re worried about missing out on your viewing in the meantime, don’t worry. Spaceway-1 was already past its expected end-of-life, having been designed for 12 years of relaying television, and today provides backup internet broadband connectivity for Alaska and the surrounding area. DirecTV is taking steps to make sure coverage is fine.
“This satellite is a backup and we do not anticipate any impacts on consumer service as we retire it. We are replacing it with another satellite in our fleet,” DirecTV told The Register. ®