Breaking Defense reports that "Russia and China are investing heavily in cyber and electronic warfare, but they’re not shutting down US satellite downlinks yet. Instead, we have met the enemy and he is us — we think."
“'In 2015 thus far, we have had 261 cases where we have been jammed from getting information from our satellites down to the ground segment,' said Gen. John Hyten, head of Air Force Space Command, at the Association of Old Crows electronic warfare conference."
"That’s 23 times a month. 'How many were caused by an adversary?' Hyten asked. 'I really don’t know. My guess is zero.'”