The craft is most famous for launching a projectile into the Comet Tempel 1 in 2005, but its mission was extended and renamed Epoxi to continue observation of other comets as well as stars with exoplanets.
Deep Impact lost contact with Earth sometime between August 11 and 14. Engineers determined a software-communications glitch reset the craft’s computer, but attempts to put the craft in safe mode have been unsuccessful.
Epoxi principal investigator Michael A’Hearn of the University of Maryland explained that Deep Impact is now spinning out of control, and engineers are working on commands that could make the craft operational.
This will be difficult without knowing the craft's orientation in space, and whether to direct their signals to Deep Impact's high-gain or low-gain antenna.
Because the craft is solar-powered, the orientation of its solar panels toward or away from the sun mean a difference between a few days or a few months of battery life. Once the craft's batteries die, there is no turning it back on, A’Hearn says.
As a result of the glitch, Deep Impact was unable to transmit images it was scheduled to take in August of the comet ISON.