|Function||Expendable launch system|
|Manufacturer||Northrop Grumman Innovation Systems|
|Cost per launch||$50 million |
|Height||23.88 metres (78.3 ft)|
|Diameter||2.34 metres (7 ft 8 in)|
|Payload to LEO|
|Mass||1735 kg (28.5°, 185 km)|
|Launch sites||Vandenberg AFB, SLC-8|
|First flight||22 April 2010|
|Last flight||15 July 2020|
|First stage – SR-118|
|Thrust||2,200 kilonewtons (490,000 lbf)|
|Second stage – SR-119|
|Thrust||1,365 kilonewtons (307,000 lbf)|
|Burn time||54 seconds|
|Third stage – SR-120|
|Thrust||329 kilonewtons (74,000 lbf)|
|Burn time||62 seconds|
|Fourth stage (Baseline) – Orion 38|
|Thrust||32.2 kilonewtons (7,200 lbf)|
|Burn time||67.7 seconds|
|Fourth stage (Optional) – Star-48V|
|Thrust||68.6 kilonewtons (15,400 lbf)|
|Burn time||84.1 seconds|
Minotaur IV, also known as Peacekeeper SLV and OSP-2 PK is an active expendable launch system derived from the LGM-118 Peacekeeper ICBM. It is operated by Northrop Grumman Innovation Systems, and made its maiden flight on 22 April 2010, carrying the HTV-2a Hypersonic Test Vehicle. The first orbital launch occurred on 26 September 2010 with the SBSS satellite for the United States Air Force.
The Minotaur IV vehicle consists of four stages and is capable of placing 1,735 kilograms (3,825 lb) of payload into a Low Earth orbit (LEO). It uses the first three stages of the Peacekeeper missile, combined with a new upper stage. On the baseline version, the fourth stage is an Orion 38. However a higher performance variant, designated Minotaur IV+, uses a Star-48V instead. A three-stage configuration (no Orion 38), designated the Minotaur IV Lite, is available for suborbital trajectories. The Minotaur IV has also been flown with multiple upper stages. A five-stage derivative, the Minotaur V, made its maiden flight on 7 September 2013.
Minotaur IV launches are conducted from SLC-8 at Vandenberg Air Force Base, LP-0B at the Mid-Atlantic Regional Spaceport, SLC-46 at Cape Canaveral Air Force Station and Pacific Spaceport Complex – Alaska Pad 1 of the Pacific Spaceport Complex – Alaska (PSCA).
|Flight No.||Date/Time (UTC)||Variant||Launch Site||Payload||Trajectory||Outcome||Remarks|
|1||22 April 2010
|Minotaur IV Lite||Vandenberg, SLC-8||HTV-2a||Suborbital||Success||Successful launch, but payload failed|
|2||26 September 2010
|Minotaur IV||Vandenberg, SLC-8||SBSS||SSO||Success|
|3||20 November 2010
|Minotaur IV HAPS||Kodiak,
|LEO||Success||STP-S26 launch. Included a Hydrazine Auxiliary Propulsion System (HAPS) to take the vehicle to a secondary orbit after placing payloads into the primary orbit.|
|4||11 August 2011
|Minotaur IV Lite||Vandenberg, SLC-8||HTV-2b||Suborbital||Success||Successful launch, but payload failed|
|5||27 September 2011
|TacSat-4||LEO||Success||First Minotaur IV+ launch|
|6||26 August 2017
|Minotaur IV / Orion 38||CCAFS, SLC-46||ORS-5||LEO||Success||Ran in a 5-stage configuration, using an extra Orion 38 motor to put ORS-5 in to an equatorial orbit.|
|7||15 July 2020
|Minotaur IV / Orion 38||MARS,
|NROL-129||LEO||Success||Carried four payloads (USA-305 to USA-308). First NRO launch on a Minotaur IV and first from Virginia's Space Coast.|
|Date/Time (UTC)||Variant||Launch Site||Payload||Trajectory||Remarks|
|2023||Minotaur IV||Vandenberg, SLC-8||NROL-174||?|
|TBD||Minotaur IV||Vandenberg, SLC-8||TacSat-5||LEO||Might launch on a Minotaur I.|
|TBD||Minotaur IV Lite||Vandenberg, SLC-8||CSM||Suborbital|
The third Minotaur IV launch, which was also known as STP-S26, deployed eight payloads. It was the 29th small launch vehicle mission in STP's 49-year history of flying DoD space experiments, STP-S26 was intended to extend previous standard interface development efforts, implementing a number of capabilities aimed at enabling responsive access to space for small experimental satellites and payloads. STP-S96 launched at 01:25 UTC on 20 November 2019 from the Kodiak Launch Complex. The launch facility contractor was Alaska Aerospace Corporation (AAC). The payloads were released in a 650 kilometres (400 mi) orbit, before the HAPS upper stage was demonstrated by deploying two ballast payloads into a 1,200 kilometres (750 mi) orbit.
The primary objective of the STP-S26 launch was to deploy STPSAT-2 (USA-287), whilst demonstrating the ability of the Minotaur IV to carry additional payloads, by deploying FASTSAT, FASTRAC, RAX, O/OREOS and FalconSat-5. A Hydrazine Auxiliary Propulsion System upper stage was flown aboard the Minotaur to demonstrate its ability to deploy payloads to multiple orbits, however only mass simulators were deployed after the HAPS burn.
The launch marked the first flight of a STP-SIV (Standard Interface Vehicle) satellite, the first use of the Multi Mission Satellite Operations Center Ground System Architecture (MMSOC GSA), the first flight of the Minotaur IV's Multi-payload Adapter (MPA), the first use of a HAPS to obtain multiple orbits on a Minotaur IV flight, the first Minotaur launch from Kodiak Launch Complex (KLC), and the first deployment of CubeSats from a Minotaur IV via Poly-PicoSatellite Orbital Deployers (P-Pods).
[T]he Space Force and the NRO have purchased at least one more Minotaur flight to deliver another classified payload to orbit. That mission, known as NROL-174, will use a Minotaur 4 rocket, the larger Minotaur variant. It is scheduled for launch in 2023, Eberly said.
"We're basically on contract for three Minotaur launches. One is a Minotaur IV, which looks like it's going to be launched from Vandenberg Space Force Base in 2023, and that's for the Space Force," said Eberly.