 The rocket featured several modifications from previous flights, including an enlarged upper stage with more fuel to accommodate a heavier payload, and an enlarged composite payload fairing with a diameter of in place of the regular aluminium fairing.The launch was originally scheduled for 20 December 2010, but was delayed to allow a leaking valve on the upper stage to be repaired.Following the repair of the leak, the launch was rescheduled for 25 December 2010.