The COTS demonstration mission was successfully conducted in September 2013, and Orbital commenced operational ISS cargo missions under the Commercial Resupply Service (CRS) program with two missions in 2014.
Regrettably, the third operational mission, CRS Orb-3, was not successful due to spectacular Antares failure during launch.
The company decided to discontinue the Antares 100 series and accelerate the introduction of a new propulsion system.
The Antares system has been upgraded with newly built RD-181 first-stage engines to provide greater payload performance and increased reliability.

In the meantime, the company had contracted with United Launch Alliance for an Atlas V launch of CRS OA-4 in late 2015 from Cape Canaveral, FL and with a second Atlas V Cygnus launch in 2016.
 The company had planned Cygnus missions for the first (CRS OA-5), second (CRS OA-6) and fourth quarters (CRS OA-7) of 2016.
Two of these flew on the new Antares 230 and one on the aforementioned second Atlas V. These three missions enabled Orbital ATK to cover their initial CRS contracted payload obligation.
This particular mission, is known as OA-8E, is part of an extension program that will enable NASA to cover the ISS resupply needs until the Commercial Resupply Services 2 contract enters in effect.
It is called OA-8E rather than OA-8, because the switch to a mix of Atlas V and the more powerful Antares 230 enabled the company to cover its original contract with just 7 flights, even counting the Orb-3 failure, and thus the E indicates that it actually is an extension above the originally contracted payload transport.

Production and integration of Cygnus spacecraft is performed in Dulles, Virginia.
The Cygnus service module is mated with the pressurized cargo module at the launch site, and mission operations are conducted from control centers in Dulles and Houston.

The launch was previously scheduled for 10 November at 8:03 AM before being moved to 11 November at 7:37:24 AM.
The 11 November launch attempt resulted in a twenty four hour recycle due to a plane flying into the restricted area with less than a minute into the count.
The Antares rocket launched the 8th Cygnus cargo vehicle on Sunday 12 November at 7:19:51 AM.
The COTS demonstration mission was successfully conducted in September 2013, and Orbital commenced operational ISS cargo missions under the Commercial Resupply Service (CRS) program with two missions in 2014. Regrettably, the third operational mission, CRS Orb-3, was not successful due to spectacular Antares failure during launch. The company decided to discontinue the Antares 100 series and accelerate the introduction of a new propulsion system. The Antares system has been upgraded with newly built RD-181 first-stage engines to provide greater payload performance and increased reliability.
In the meantime, the company had contracted with United Launch Alliance for an Atlas V launch of CRS OA-4 in late 2015 from Cape Canaveral, FL and with a second Atlas V Cygnus launch in 2016.  The company had planned Cygnus missions for the first (CRS OA-5), second (CRS OA-6) and fourth quarters (CRS OA-7) of 2016. Two of these flew on the new Antares 230 and one on the aforementioned second Atlas V. These three missions enabled Orbital ATK to cover their initial CRS contracted payload obligation. This particular mission, is known as OA-8E, is part of an extension program that will enable NASA to cover the ISS resupply needs until the Commercial Resupply Services 2 contract enters in effect. It is called OA-8E rather than OA-8, because the switch to a mix of Atlas V and the more powerful Antares 230 enabled the company to cover its original contract with just 7 flights, even counting the Orb-3 failure, and thus the E indicates that it actually is an extension above the originally contracted payload transport.
Production and integration of Cygnus spacecraft is performed in Dulles, Virginia. The Cygnus service module is mated with the pressurized cargo module at the launch site, and mission operations are conducted from control centers in Dulles and Houston.
The launch was previously scheduled for 10 November at 8:03 AM before being moved to 11 November at 7:37:24 AM. The 11 November launch attempt resulted in a twenty four hour recycle due to a plane flying into the restricted area with less than a minute into the count. The Antares rocket launched the 8th Cygnus cargo vehicle on Sunday 12 November at 7:19:51 AM.
Cygnus CRS OA-8E