Roamy here. Cosmic rays and high energy protons can do strange things to electronics on spacecraft. Latchups, burnouts, and data errors are all filed under the category “single event effects”. Think of it as getting the Blue Screen of Death on orbit. When the spacecraft is communicating with the operators on the ground, usually it can be recovered. For example, the Spirit rover on Mars was stuck in a reboot loop (scroll down to January 23, 2004) where it rebooted itself more than 60 times in three days. It turned out to be a problem with the flash memory onboard – it was reformatted, the problem went away, and the science mission continued. Spirit rebooted itself a couple of times in April 2009, but given how long it’s lasted on Mars, no one seemed too surprised by that. NASA report RP-1375 has a pretty good list of the satellites recovered from single event effects (Intelsat K, Anik E-1), the ones that were recovered but had a shortened lifetime (Anik E-2, GOES-7), or were completely lost (GOES-4, DSCS-II).
Now take the case of the Galaxy 15 satellite. It lost contact with the ground last April but kept broadcasting signals, interfering with other satellites. Finally, last month, the batteries ran down enough for it to go into safe mode and start listening to the ground again. It should be able to go back into service and hopefully not have a shortened lifetime.
Y’know, if you have to take a zombie down, double-tap. (reference link)