The unmanned Cygnus spacecraft is set to launch on its return-to-flight mission on December 3rd, 2015. The spacecraft will bring over 3500 kilograms of research materials, supplies and hardware to the International Space Station.
The Cygnus is scheduled to launch at 5:55 p.m EST (2255 GMT) from Cape Canaveral Air Force Station in Florida aboard a United Launch Alliance Atlas V rocket. This is the fourth resupply mission performed by Orbital ATK, out of eight that it will perform under its contract with NASA.
The U.S. Air Force has reported that there is a 60% chance that weather conditions will permit the launch. If the resupply mission leaves on schedule, the spacecraft is expected to reach the ISS on Sunday, December 6th. If it is unable to be launched today, it will be launched tomorrow, and arrive on December 7th or 8th. It will then be captured by the station's Canadarm2 robotic arm, operated by astronaut Kjell Lindgren, with assistance from astronaut Scott Kelly.
NASA TV will be providing live coverage of the launch online: