Minotaur IV

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Minotaur IV
Launch of the first Minotaur IV Lite
FunctionExpendable launch system
Cost per launch$50 million [1]
Height23.88 metres (78.3 ft)
Diameter2.34 metres (7 ft 8 in)
Mass86,300 kg
Payload to LEO
Mass1735 kg (28.5°, 185 km)
Associated rockets
Derivative workMinotaur V
Launch history
Launch sitesVandenberg AFB, SLC-8
Total launches7
First flight22 April 2010
Last flight15 July 2020
First stage – SR-118
Powered by1 Solid
Maximum thrust2,200 kilonewtons (490,000 lbf)
Second stage – SR-119
Powered by1 Solid
Maximum thrust1,365 kilonewtons (307,000 lbf)
Burn time54 seconds
Third stage – SR-120
Powered by1 Solid
Maximum thrust329 kilonewtons (74,000 lbf)
Burn time62 seconds
Fourth stage (Baseline) – Orion 38
Powered by1 Solid
Maximum thrust32.2 kilonewtons (7,200 lbf)
Burn time67.7 seconds
Fourth stage (Optional) – Star-48V
Powered by1 Solid
Maximum thrust68.6 kilonewtons (15,400 lbf)
Burn time84.1 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 Space Systems, and made its maiden flight on 22 April 2010, carrying the HTV-2a Hypersonic Test Vehicle.[2][3][4] 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).[5][6] 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).

Launch history[edit]

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[7]
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
Minotaur IV+ Kodiak,
TacSat-4 LEO Success First Minotaur IV+ launch
6 26 August 2017
Minotaur IV / Orion 38 CCAFS, SLC-46 ORS-5 LEO[9] 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[9] Success Carried four payloads (USA-305 to USA-308). First NRO launch on a Minotaur IV and first from Virginia's Space Coast.[11]

Planned launches[edit]

Date/Time (UTC) Variant Launch Site Payload Trajectory Remarks
February 2024[12] Minotaur IV Vandenberg, SLC-8 NROL-174 LEO
September 2024[13] Minotaur IV ? LEO STP-S29A mission
May 2025[14] Minotaur IV Vandenberg, SLC-8 EWS-I 1 LEO USSF-261S-A mission
TBD Minotaur IV Lite Vandenberg, SLC-8 CSM Suborbital
TBD Minotaur IV ?


ORS mission
TBD Minotaur IV ?


ORS mission


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,[15] 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 an 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).[15]

See also[edit]


  1. ^ Stephen Clark (18 November 2010). "Minotaur rocket poised to send research to new heights". Spaceflight Now.
  2. ^ "Orbital Successfully Launches First Minotaur IV Rocket for U.S. Air Force" (Press release). Orbital Sciences Corporation. 27 April 2010.
  3. ^ "Air Force Space Officials Prepare To Launch First Minotaur IV". Air Force News Service. 16 April 2010. Archived from the original on 29 July 2012.
  4. ^ Graham, William (22 April 2010). "First Minotaur IV launches with Hypersonic Test Vehicle". NASAspaceflight.com.
  5. ^ "Minotaur IV-V-VI User's Guide" (PDF). Northrop Grumman Corporation. 2020. Retrieved 19 November 2022.
  6. ^ Krebs, Gunter. "Minotaur-3/-4/-5 (OSP-2 Peacekeeper SLV)". Gunter's Space Page. Retrieved 4 March 2009.
  7. ^ a b Schaub, Michael B.; Schwartz, Patrick C. "Launches". Mission Set Database. NASA/Honeywell-TSI. Archived from the original on 20 March 2009. Retrieved 23 April 2010. Public Domain This article incorporates text from this source, which is in the public domain.
  8. ^ Hope, Dan (10 August 2011). "DARPA Readies Hypersonic Aircraft for Mach 20 Launch Test". Space.com. Retrieved 10 August 2011.
  9. ^ a b Clark, Stephen. "Minotaur rocket selected to launch military satellite in 2017". Spaceflight Now.
  10. ^ Clark, Stephen. "Launch Schedule". Spaceflight Now. Retrieved 4 July 2020.
  11. ^ "NROL-129 Launch Press Kit" (PDF). NRO. Retrieved 9 July 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  12. ^ "Minotaur IV - NROL-174". Next Spaceflight. Retrieved 22 December 2023.
  13. ^ Erwin, Sandra (22 April 2023). "Astra wins $11.5 million contract to launch military experimental payloads". SpaceNews.com. Retrieved 30 April 2023.
  14. ^ "Space Systems Command Awards $45.5M Launch Service Order to Northrop Grumman Systems Corporation for Prototype EWS Mission". NASASpaceFlight. 25 May 2023. Retrieved 25 May 2023.
  15. ^ a b Brinton, Turner. "Air Force's STP-S26 Mission Loaded with New Technologies". SPACENEWS. Retrieved 8 December 2016.

External links[edit]