jfruh writes "On January 21, 2004, the Spirit Mars rover, which had been cheerfully collecting data and sending it back to Earth for the two weeks since it had landed, suddenly ground to a halt. Mission controllers at the Jet Propulsion Laboratory were getting pings indicating that the rover was alive, but that was it. Over the next eleven days, the JPL team coaxed the rover back to life, eventually discovering that the heart of the problem lay in a DOS memory management bug interacting with insufficiently tested third-party code." Link to Original Source
Vital papers will demonstrate their vitality by spontaneously moving
from where you left them to where you can't find them.