The NASA spacecraft Deep Impact had been studying comets for eight years before NASA "reluctantly" admitted defeat in restoring communication with the probe. The spacecraft hasn't been in communication with NASA since early August.
Deep Impact was first launched in 2005 to study the comet Tempel 1, launching an impactor into the comet to remove debris so that photos could be taken. In recent years, the probe was dispatched to rendezvous flyby with comet Hartley 2 in 2010. Earlier this year, it photographed the ISON comet. (ISON is a candidate to be the "comet of the century" when it passes through our solar system in November.) The comet could be able to be brighter than the moon when it passes through, and may even be capable of being seen during the day.
Deep Impact traveled 4.7 billion miles over the course of its lifetime that was three to four times longer than expected. The information the probe collected on the cometary population revealed remarkable diversity and also brought about new information of the development of our solar system. One of the biggest accomplishments of Deep Impact was the information it collected on comet's tails — namely, that the composition of the tail is remarkably similar to their insides. This discovery allows astronomers to make more inferences regarding the comet's interior.
Unfortunately, the new data, including over 500,000 images — many of them of ISON — will now never make it home.
NASA described the communication issue with Deep Impact as a glitch with "computer time tagging" interfering with the craft's orientation, making it impossible for NASA to ascertain the radio signal from the probe. The solar panels cannot be moved to face the sun, drastically limiting the lifespan of Deep Impact and freezing its equipment.
The spacecraft is now doomed to circle the solar system as space junk.