Minotaur VI

Minotaur VI is a proposed expendable launch system derived from the LGM-118 Peacekeeper ICBM. It is a member of the Minotaur rocket family and a higher-performance derivative of the Minotaur IV. The base Minotaur VI consists of a Minotaur IV+ rocket with an additional SR118 first stage motor for improved performance. Minotaur VI is optimized for low Earth orbit (LEO) missions, and can send 3144 kg to such an orbit. The Minotaur VI+ variant, however, features a Star 37FM sixth stage and is primarily intended for higher-energy missions.

The Minotaur VI and VI+ rockets are capable of launching from LP-1 at the Pacific Spaceport Complex – Alaska as well as SLC-46 at Cape Canaveral Space Force Station. Other Minotaur launch complexes, including Vandenberg Space Launch Complex 8 and MARS LP-0B, are unable to launch the vehicle without modifications because of limited integration tower height.

As of May 2024, no Minotaur VI launches have been performed and none are currently scheduled.

Description
Minotaur VI was developed by Orbital Sciences (now owned by Northrop Grumman). Minotaur VI would be used for low Earth orbit and Sun-synchronous orbit missions. Minotaur VI+ is also available for high-energy trajectories such as geostationary transfer orbit or trans-lunar injection thanks to an additional sixth stage motor.

The Minotaur IV family (which includes Minotaur VI) is derived from the LGM-118 Peacekeeper intercontinental ballistic missile (ICBM), deployed from 1985 until 2005. The Minotaur VI utilizes decommissioned Peacekeeper solid rocket motors, which compose the first three stages in all Minotaur IV rockets and derivatives. This relatively simple architecture allows Minotaur to be launched from essentially anywhere in the US through the use of mobile launch facilities - although this capability has never been needed. Because of its use of decommissioned ICBM components, Minotaur VI can only be used to launch US government missions.

Two payload fairing options are available for Minotaur VI. The standard fairing, which has so far flown on every Minotaur IV and V rocket, has a 92 in diameter and is composed of graphite epoxy sheets with an aluminum honeycomb core. The fairing features one payload access door, although more can be added if requested by a customer. The 92-inch fairing was originally developed for the Taurus rocket. A second fairing option with a 110 in diameter is offered for larger payloads.

On the Minotaur VI+, the Star 37 sixth stage is contained within the fairing.

Minotaur VI
The standard Minotaur VI rocket is composed of five stages. The first and second stage SR118 motors provide 2224 kN of thrust during their back-to-back 56.6-second burns, followed by stage separation and third-stage ignition. The third stage, powered by an SR119 motor, burns for 61 seconds and provides an average thrust of 1223 kN. The fourth stage then burns for 72 seconds, with an average thrust of 289 kN. The initial four stages all have thrust vector control, allowing them to steer the rocket downrange by gimballing the motor nozzles. The third and fourth stages also feature extendable nozzles, allowing for improved performance in the upper portions of Earth's atmosphere as well as the vacuum of space.

The Star 48BV fifth stage burns for 85.2 seconds with an average thrust of 68.63 kN and also features thrust vectoring, which is uncommon for Star 48 motors. The Star 48 motor has also seen use on the Atlas V, Delta IV, and Space Shuttle, alongside over 70 missions on the Delta II.

Minotaur VI is primarily intended for low Earth orbit missions, with a rated capacity of 3144 kg to LEO and 2400 kg to SSO.

Minotaur VI+
The Minotaur VI+ builds off the standard Minotaur VI by incorporating a Star 37FM sixth stage. This allows the VI+ variant to either send additional payload to LEO (up to 3360 kg) or send smaller payloads onto higher-energy trajectories. The Star 37FM can fly either in a spin-stabilized configuration or in a three-axis controlled variant, although some performance is sacrificed on the latter configuration.

Minotaur VI+ can send up to 866 kg to geostationary transfer orbit, 560 kg to trans-lunar injection, and 300 kg to a trans-Mars injection.