One might hope that the communications satellites suspended in orbit above the earth might be one component of the planet’s technology infrastructure that is safely out of harm’s way.

However, at the end of last year, a report from the US-China Economic and Security Review Commission claimed that hackers, believed to be operating from China, had managed in 2008 to interfere with two US government satellites.

The hackers took control of the Landsat-7 and Terra AM-1 satellites for a grand total of 12 minutes and two minutes respectively, the report claimed.

But as satellite communications enthusiast Paul Marsh explained at the London Security B-Sides event in April, there are reasons to doubt the reports. He spoke about a similar story, reported in the late 1990s, about hackers supposedly accessing UK military satellite communications network SkyNet and ‘nudging’ one satellite out of synch.

“First off,” he explained, “jamming a satellite is easy to trace. Every time a command is sent up to the satellite, it gets counted. If you send one wrong frame up to then a red light will start flashing at RAF Oakingham.”

Marsh presented some back- of-the-envelope calculations for the power that would be needed to launch a “brute force” attack on a Skynet satellite.

He used Google Earth to estimate that the dish that controls Skynet satellites from RAF Oakingham is about seven meters in diameter, meaning the transmitted power is about five million watts.

“That’s a lot,” said Marsh. In fact, it is about as much power as is produced by a train. A typical wind turbine has an output of just one to the three million watts.

Marsch said he doubted whether hackers would have had the wherewithal to send tracking and telemetry data up to the Skynet satellite. Whether Chinese hackers have that capability now is just one more matter of speculation to add to the opaque field of cyber warfare.