Orbital ATK announced it conducted a full-power "hot fire" test of the upgraded first stage propulsion system of its Antares medium-class rocket using new RD-181 main engines, built by Energomash in Russia. The 30-second test took place on 31 May 2016 at Virginia Space’s Mid-Atlantic Regional Spaceport (MARS) Pad 0A. Initial indications are that the test was fully successful.