Antares (Taurus-2)

Antares-110 (A-One) [NASA]

Orbital is currently in development of a medium-class launch vehicle, dubbed Antares (formerly Taurus II), to extend its family of small-class Pegasus, Taurus and Minotaur launchers. The Antares design adapts elements from these proven launch technologies along with hardware from one of the world's leading launch vehicle integrators to provide low-cost and reliable access to space for civil, commercial and military Delta II-class payloads.

The first stage structure will be manufactured by ukrainian Yuzhnoe company and features two AJ26-62 (americanized NK-33) engines. The stage structure is based on the Zenit launch vehicle. The second stage is a Castor-30, which is based on a shortened Castor-120 solid rocket motor. A Castor-30A second stage will help propel the first two Antares-110 rockets into orbit, then a higher-performing Castor-30B motor will be used with the Antares-120 on the third and fourth flights in 2012. The optional third stage called BTS (Bi-Propellant Third Stage, formerly ORK, Orbit Raising Kit) is based on the propulsion system of Orbital's Star-2 satellite bus. For high energy orbits a Star-48BV can be used as third stage.

An enhanced version called Antares-130 featuring a Castor-30XL upper stage will be used for later flights.

Antares will be designed to achieve a 98% or greater launch reliability. It will be developed, manufactured and launched using identical management approaches, engineering standards and production and test processes used in Orbital's other major launch vehicles.

The vehicle will be launched from a new launch pad LA-0A at Wallops Island, where the former Conestoga launch pad was located.

The different variants are encoded by a three digit number:
1. digit = first stage (1 = Standard first stage
2. digit = second stage (1 = Castor-30A, 2 = Castor-30B, 3 = Castor-30XL)
3. digit = third stage (0 = none, 1 = BTS, 2 = Star-48BV)