One of NASA's Earth observation satellites was hacked twice back in 2008, the TPM news website reports.

In an e-mail to TPM, NASA public affairs officer Trent Perrotto confirmed two incidents had affected the Terra AM-1 satellite.

"NASA experienced two suspicious events with the Terra spacecraft in the summer and fall of 2008," Perrotto wrote. "We can confirm that there was no manipulation of data, no commands were successfully sent to the satellite, and no data was captured. NASA notified the Department of Defense, which is responsible for investigating any attempted interference with satellite operations."

He further wrote that NASA has "created a working group to establish and implement an agency-wide space protection program."

A report on the Bloomberg website indicates that computer hackers, possibly from the Chinese military, infiltrated two U.S. government satellites four times in 2007 and 2008.

Bloomberg bases its piece on a draft of the annual report of the U.S.-China Economic and Security Review Commission and reports that the hacking took place through a ground station in Norway.

The alleged interference with the Terra AM-1 satellite took place twice, for two minutes in June 2008 and nine minutes in October of that year, Bloomberg attributes to the draft report.

The report also indicates a Landsat-7 Earth-observation satellite was hacked for 12 or more minutes in October 2007 and July 2008, Bloomberg reports.

"Such interference poses numerous potential threats, particularly if achieved against satellites with more sensitive functions," Bloomberg quotes the draft report as reading. "Access to a satellite's controls could allow an attacker to damage or destroy the satellite. An attacker could also deny or degrade as well as forge or otherwise manipulate the satellite's transmission."

NASA's Perrotto said he was not in a position to confirm any potential events involving Landsat-7, which NASA built for the U.S. Geological Survey.