PK-Minotaur

Orbital Sciences Corporation

Orbital Sciences Corporation announced that it has been awarded a major contract by the U.S. Air Force to provide space launch and missile defense target vehicles using deactivated Peacekeeper ICBM assets under the Orbital/Suborbital Program-2 (OSP-2).
Orbital will combine Peacekeeper rocket motors with commercial launch vehicle technology derived from its Pegasus and Taurus rockets to develop and operate low-cost vehicles to launch U.S. government-funded satellites into low-Earth orbit. Capable of boosting payloads more than 1.75 tons into orbit.
Under the Minuteman portion of the contract, Orbital will continue to provide target and Minotaur space launch services.

The vehicle consists of three Peacekeeper solid rocket stages, a commercial Orion-38 fourth stage motor and subsystems derived from our established space launch boosters. Under a 10-year contract with the U.S. Air Force Space and Missile Systems Center, Orbital will develop and operate the low-cost Minotaur-IV vehicle to launch U.S. government-funded satellites into low-Earth orbit.

The Minotaur-IV  incorporates a standard 92-inch fairing from our Taurus booster and supports dedicated or shared launch missions. Capable of boosting payloads more than 1,750 kg into LEO or 998 kg into SSO.

Minotaur-V  is a 5-stage evolutionary version of the Minotaur-IV to launch small spacecraft into high energy trajectories, including geosynchronous transfer orbits and translunar missions. The first three stages of the Minotaur-V are the unmodified Peacekeeper solid rocket motors. The forth and fifth stages are commercial motors. The stage four motor is nominally a Star-48BV configuration. the fifth stage can be either attitude controlled or spinning. The attitude controlled version nominally uses the same Orion-38 motor that has been extensively flight demonstrated on multiple Orbital launch vehicles. For a spinning configuration, a Star-37FMV is used to provide maximum performance. The Minotaur avionics, structures, and fairing are common with the Minotaur-IV SLV. Capable of boosting payloads  than 553 to 710 kg  into GTO.

Minotaur-VI  is a Minotaur-IV+ stretched by a second SR-118 motor on the first stage.

Castor-120XL
This variant of the Castor-120 predecessor is used as a first or second stage in commercial launch vehicles and provides improved performance over the baseline configuration. A version of this motor was static tested for the U.S. Air Force as part of the Large Class Stage development program, however the motor is being updated to tailor burn rates and improve performance, as well as utilize common materials & processes to improve cost control for launch vehicle providers.
In addition to Athena family, Castor-120XL is in preparation for Minotaur-C (ex-Taurus family) and Minotaur-I (commercial version) which are in the process of being merged into one sub-family under Minotaur-I.