On Friday, NASA officially abandoned its attempts to regain contact with the Deep Impact comet probe and have declared the mission over. The space agency lost contact with the unmanned spacecraft in August and repeated attempts to reestablish the link have failed.
NASA says that the exact cause of the communications failure is unknown, but engineers suspect that the problem lies in computer time tagging, which caused a loss of attitude control in Deep Impact and sent it tumbling. Unable to aim its radio antennas at Earth, contact could not be reestablished and the probe’s solar panels couldn't charge the batteries properly to power the systems and keep the electronics warm. This means that the spacecraft will eventually freeze and become inoperable.
“Despite this unexpected final curtain call, Deep Impact already achieved much more than ever was envisioned," says Lindley Johnson, the Discovery Program Executive at NASA Headquarters and the Program Executive for the mission. "Deep Impact has completely overturned what we thought we knew about comets and also provided a treasure trove of additional planetary science that will be the source data of research for years to come.”
Launched in 2005, Deep Impact has traveled 4.7 billion miles (7.58 billion km). On its encounter with the comet Tempel 1, Deep impact fired an impactor containing and instrument package into the comet’s nucleus, and was later put on extended missions that saw it flyby comet Hartley 2 in 2010, comet C/2009/1 in 2012 and comet ISON in 2013.