Complex sentence: Command Control was expecting the rover to contact Earth on 12 February 2014 had it endured its second lunar night, since it did not transmit any signals, the rover was officially declared permanently inoperative.
Split into simpler sentences: Command Control was expecting the rover to contact Earth on 12 February 2014 had it endured its second lunar night. Since it did not transmit any signals, the rover was officially declared permanently inoperative.