Minotaur IV
 Launch of the first Minotaur IV Lite | |
| Function | Small-lift launch vehicle |
|---|---|
| Manufacturer | Northrop Grumman |
| Cost per launch | $50 million (2010) |
| Size | |
| Height | 23.88 m (78.3 ft) |
| Diameter | 2.34 m (7 ft 8 in) |
| Mass | 86,300 kg (190,300 lb) |
| Stages | 4 |
| Capacity | |
| Payload to LEO | |
| Altitude | 200 km (120 mi) |
| Orbital inclination | 28.5° |
| Mass | IV: 1,591 kg (3,508 lb) IV+: 1,837 kg (4,050 lb) |
| Payload to sub-orbital | |
| Mass | IV Lite: 3,000 kg (6,600 lb) |
| Associated rockets | |
| Family | Minotaur |
| Based on | LGM-118 Peacekeeper |
| Derivative work | |
| Launch history | |
| Status | Active |
| Launch sites | |
| Total launches | 9 |
| Success(es) | 9 |
| First flight | April 22, 2010 |
| Last flight | April 7, 2026 (most recent) |
| First stage – SR-118 | |
| Maximum thrust | 2,224 kN (500,000 lbf) |
| Specific impulse | 229 s (2.25 km/s) |
| Burn time | 56.6 seconds |
| Propellant | HTPB |
| Second stage – SR-119 | |
| Maximum thrust | 1,223 kN (275,000 lbf) |
| Specific impulse | 308 s (3.02 km/s) |
| Burn time | 61 seconds |
| Propellant | HTPB |
| Third stage – SR-120 | |
| Maximum thrust | 289 kN (65,000 lbf) |
| Specific impulse | 300 s (2.9 km/s) |
| Burn time | 72 seconds |
| Propellant | NEPE |
| Fourth stage (Minotaur IV) – Orion 38 | |
| Maximum thrust | 32.2 kN (7,200 lbf) |
| Specific impulse | 288 s (2.82 km/s) |
| Burn time | 67.7 seconds |
| Propellant | HTPB |
| Fourth stage (Minotaur IV+) – Star 48BV | |
| Maximum thrust | 68.6 kN (15,400 lbf) |
| Specific impulse | 288 s (2.82 km/s) |
| Burn time | 84.1 seconds |
| Propellant | HTPB |
Minotaur IV, also known as Peacekeeper SLV and OSP-2 PK, is a small-lift launch vehicle repurposed from the retired LGM-118 Peacekeeper, an intercontinental ballistic missile (ICBM). It is operated by Northrop Grumman and first flew on April 22, 2010, carrying the HTV-2a Hypersonic Test Vehicle. Its first orbital launch occurred on September 26, 2010, placing the Space Based Space Surveillance (SBSS) satellite into orbit for the United States Air Force.
Part of the Minotaur family of solid-fuel launch vehicles repurposed from retired ICBMs, the four-stage Minotaur IV can deliver up to 1,591 kilograms (3,508 lb) to low Earth orbit. Its first three stages use decommissioned Peacekeeper missile motors, while the baseline fourth stage is an Orion 38. The enhanced Minotaur IV+ replaces this with a Star 48BV upper stage, while the three-stage Minotaur IV Lite omits the fourth stage for suborbital missions. A five-stage derivative, Minotaur V, flew on September 7, 2013.
Launches have been conducted from SLC-8 at Vandenberg Space Force Base, LP-0B at the Mid-Atlantic Regional Spaceport, SLC-46 at Cape Canaveral Space Force Station, and Pad 1 at the Pacific Spaceport Complex – Alaska.