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 240 km × 260 km with an orbital inclination of 51.6°, the same launch profile it uses for Orbital's Cygnus cargo supply missions to the International Space Station (ISS) for NASA.

Antares, known during early development as Taurus II, is an expendable launch system developed by Orbital Sciences Corporation and the Pivdenne Design Bureau to launch the Cygnus spacecraft to the International Space Station as part of NASA's COTS and CRS programs. Able to launch payloads heavier than 8,000 kg (18,000 lb) into low Earth orbit, Antares is the largest rocket operated by Northrop Grumman. Antares launches from the Mid-Atlantic Regional Spaceport and made its inaugural flight on April 21, 2013. Antares 100 was retired in 2014 and series 200 was retired in 2023 due to component unavailability. As of January 2024 Antares 300 is under development.