Hackers in the Chinese military are suspected to have interfered with two US satellites used for climate and terrain monitoring four times during 2007 and 2008, according to a congressional commission report due to be released next month.

"Such interference poses numerous potential threats, particularly if achieved against satellites with more sensitive functions," according to the draft report. "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."

The Landsat-7 Earth-observation satellite, managed by NASA experienced at least 12 minutes of interference in October 2007 and in July 2008. The second satellite, Terra-AM-1 also experienced interference for two minutes in June 2008 and another nine minutes in October of the same year.

Access was gained through the Svalbard Satellite Station in Spitsbergen, Norway, which "routinely relies on the Internet for data access and file transfers." Bloomberg said the report didn't give further details on the explanation of the term "interference" but noted that the hackers completed the steps required to command the Terra-AM-1 satellite, they didn't exercise the ability to use them, however.

While China was not directly accused of involvement, the report hints that China is behind most major incidents involving cybercrimes on the US government in recent years. In the commissions 2009 report it said, "individuals participating in ongoing penetrations of US networks have Chinese language skills and have well established ties with the Chinese underground hacker community." That doesn't provide proof they had Chinese ties and officials have long denied any involvement in attacks that would endanger the security interests of any country, including the US.

It did appear consistent with China's military policies of disabling enemies' space systems and in particular, ground-based infrastructures like satellite control stations. Since those who breached the satellite defenses have obscured themselves, it's unlikely they'll ever be known.