An Antares rocket carrying Orbital's Cygnus cargo logistics spacecraft is scheduled to lift off from Pad-0A at the Mid-Atlantic Regional Spaceport at Wallops Island, Virginia on Oct. 28, 2014 at 6:22 p.m. EDT (2222 GMT).
Antares will boost Cygnus to its initial target orbit, from which Cygnus will use its on-board thrusters to raise its orbit to rendezvous and berth with the International Space Station (ISS) approximately three days after launch. For this mission Cygnus will carry approximately 5,050 lbs. (2,290 kg) of cargo to the ISS for NASA.
Orb-3 is the fourth Cygnus cargo mission to the ISS and the fifth Antares launch in the last 18 months.
The two-stage Antares space launch vehicle utilizes a liquid-fueled first stage powered by two Aerojet Rocketdyne AJ26 engines and a solid motor ATK CASTOR 30XL upper stage to boost Cygnus into orbit. The powered launch sequence will last about ten minutes from liftoff through the separation of Cygnus from the launch vehicle.
This mission is the first to use the larger, more powerful CASTOR 30XL second stage motor.
After separation from Antares, Cygnus will deploy its solar arrays and undergo initial checkout. The spacecraft will conduct a series of thruster burns to raise its orbit to bring it within 4 km of the ISS prior to receiving authorization to autonomously rendezvous with the station.
When the vehicle approaches to within 12 meters, the astronauts will use the station's robotic arm to grapple Cygnus and berth it to the Harmony node of the station. Cygnus is planned to remain berthed at the ISS for approximately five weeks during which time the station crew will load Cygnus with materials for disposal. At the end of the mission Cygnus will depart the station and reenter the Earth’s atmosphere.