Spy satellites are launched in secret, their orbits are not announced and the pictures they take are rarely released. But sometimes information on their operations is inadvertently released. For example, those obnoxious pop up ads on the internet for X-10 wireless cams operate on the same frequency as many space based radars. People using them in remote locations note that the X-10 transmissions get hosed from time to time, indicating a radar overhead taking a picture. Some reports indicate getting zapped about once a month. The Soviet Union used technology like this to keep track of our radar satellites during the Cold War (and probably still do.)