Antares A-ONE mission was the maiden flight of Orbital Sciences Corporation' Antares launch vehicle including the ascent to space and accurate delivery of a simulated payload, the Cygnus Mass Simulator (CMS), which was launched 21 April 2013. It was launched from Pad 0A at the Mid-Atlantic Regional Spaceport (MARS), Wallops Flight Facility, Virginia. The simulated payload simulates the mass of the Cygnus cargo spacecraft. This dummy payload was sent into an orbit of 223 km × 237 km (139 mi × 147 mi) with an orbital inclination of 51.63°, the same launch profile it will use for Orbital's Cygnus cargo supply missions to the International Space Station (ISS) for NASA.
This launch along with several other activities leading up to it, are paid milestones under NASA's Commercial Orbital Transportation Services (COTS) program.