Taco Cowboy writes "'NASA is calling off attempts to find its Deep Impact comet probe after a suspected software glitch shut down radio communications in August, officials said on Friday.' Last month, engineers lost contact with Deep Impact and unsuccessfully tried to regain communications. The cause of the failure was unknown, but NASA suspects the spacecraft lost control, causing its antenna and solar panels to be pointed in the wrong direction. NASA had hoped Deep Impact would play a key role in observations of the approaching Comet ISON, a suspected first-time visitor to the inner solar system that was discovered in September 2012 by two Russian astronomers. The comet is heading toward a close encounter with the sun in November, a brush that it may not survive."
Deep Impact has had a pretty good run, though: from its original mission to launch a copper slug at a comet
(hence the name), to looking for Earth-sized planets