While it might seem rather terrifying to think about anyone being able to hack into satellites thousands of miles away hanging precariously above our collective heads, it was back in 2007 and 2008 that this reported incident actually took place. It's just today though that the report has surfaced via Bloomberg who state that a congressional commission annual report (to be released next month) has outlined the interference which took place two times, once in 2007, and another inside 2008. China has reportedly denied any involvement.
The first incidents at hand took place via a ground station in Norway and connect to a Landsat-7 earth observation satellite system. This unit experienced "12 or more minutes" of interference once in October of 2007 and once in July of 2008 according to the report. In addition, or perhaps in a completely related set of events, the report outlines two more incidents in which hackers interfered with a Terra AM-1 earth observation satellite. These two hacks took place for 2 minutes in June of 2008 and for nine minutes in October of that same year.
While the draft doesn't specifically accuse the Chinese government of either sponsoring or conducting the four attacks, it does say that each of the "breaches" are consistent with what they've found in Chinese military writings that advocate disabling an enemy's space systems. In particular they seem to have found the words "ground-based infrastructure, such as satellite control facilities" quite interesting. The report includes the following:
“Individuals participating in ongoing penetrations of U.S. networks have Chinese language skills and have well established ties with the Chinese underground hacker community. … These relationships do not prove any government affiliation.” - Bloomberg quoted U.S.-China Economic and Security Review Commission report
Meanwhile the report notes that all four incidents took place at the commercially operated Svalbard Satellite Station in Spitsbergen, Norway. They also note that this station “routinely relies on the Internet for data access and file transfers.” Finally, in noting specifically the October 2008 incident with the Terra AM-1, a satellite managed by NASA by the way, “the responsible party achieved all steps required to command the satellite." Of course as far as we know, the hackers have never utilized the control in the time since the supposed attack.