|   Minotaur I with NFIRE at MARS  | |
| Function | Small expendable launch system | 
|---|---|
| Manufacturer | Northrop Grumman | 
| Country of origin | United States | 
| Size | |
| Height | 19.21 metres (63.0 ft) | 
| Diameter | 1.67 metres (5 ft 6 in) | 
| Mass | 36,200 kilograms (79,800 lb) | 
| Stages | 4 or 5 | 
| Capacity | |
| Payload to LEO | |
| Mass | 580 kilograms (1,280 lb) | 
| Payload to SSO | |
| Mass | 331 kilograms (730 lb) | 
| Launch history | |
| Status | Active | 
| Launch sites |  Vandenberg SLC-8  MARS LP-0B  | 
| Total launches | 13 | 
| Success(es) | 13 | 
| First flight | 27 January 2000 | 
| Last flight | 18 June 2024 | 
| First stage –M55A1 | |
| Powered by | 1 Solid | 
| Maximum thrust | 935 kilonewtons (210,000 lbf) | 
| Propellant | Solid | 
| Second stage –SR19 | |
| Powered by | 1 Solid | 
| Maximum thrust | 268 kilonewtons (60,000 lbf) | 
| Propellant | Solid | 
| Third stage –Orion 50XL | |
| Powered by | 1 Solid | 
| Maximum thrust | 118.2 kilonewtons (26,600 lbf) | 
| Burn time | 74 seconds | 
| Propellant | Solid | 
| Fourth stage –Orion 38 | |
| Powered by | 1 Solid | 
| Maximum thrust | 34.8 kilonewtons (7,800 lbf) | 
| Burn time | 68 seconds | 
| Propellant | Solid | 
The Minotaur I,or just Minotaur is an American expendable launch system derived from the Minuteman II missile. [1] It is used to launch small satellites for the US Government,and is a member of the Minotaur family of rockets produced by Orbital Sciences Corporation (now Northrop Grumman). [2]
The Minotaur I is the follow-on to the Orbital Sciences' Taurus (later renamed the "Minotaur-C" [3] ) launch vehicle,combining the original Taurus's booster stage with a second stage from a Minuteman missile. [4]
Minotaur I rockets consist of the M55A1 first stage and SR19 second stage of a decommissioned Minuteman missile. [1] The Orion 50XL and Orion 38,from the Pegasus rocket,are used as third and fourth stages. A HAPS (Hydrazine Auxiliary Propulsion System) upper stage can also be flown if greater precision is needed,or the rocket needs to be able to maneuver to deploy multiple payloads. [5] It can place up to 580 kilograms (1,280 lb) of payload into a 185-kilometer (115 mi) low Earth orbit at 28.5 degrees of inclination. [1]
The Minotaur I is 69 feet tall and 5 feet wide. [6]
Initially Minotaur I launches are conducted from Space Launch Complex 8 at the Vandenberg Air Force Base. Starting with the launch of TacSat-2 in December 2006,launches have also been conducted from Pad 0B at the Mid-Atlantic Regional Spaceport on Wallops Island. [5]
There have been thirteen launches of the Minotaur I,all successful.
| Flight | Date (UTC) | Payload | Launch pad | Trajectory | Result | 
|---|---|---|---|---|---|
| 1 | January 27,2000 03:03:06  | JAWSat (P98-1) (FalconSat1 / ASUSat1 / OCSE / OPAL) | Vandenberg SLC-8 | LEO | Success [7] | 
| 2 | July 19,2000 20:09:00  | MightySat II.1 (Sindri,P99-1) / MEMS 2A / MEMS 2B | Vandenberg SLC-8 | LEO | Success [8] | 
| 3 | April 11,2005 13:35:00  | XSS-11 |   Vandenberg SLC-8  | LEO | Success [9] | 
| 4 | September 23,2005 02:24:00  | Streak (STP-R1) |   Vandenberg SLC-8  | LEO | Success [10] | 
| 5 | April 15,2006 01:40:00  | COSMIC (FORMOSAT-3) | Vandenberg SLC-8 | LEO | Success [11] | 
| 6 | December 16,2006 12:00  | TacSat-2 / GeneSat-1 |   MARS LP-0B  | LEO | Success [12] | 
| 7 | April 24,2007 06:48  | NFIRE |   MARS LP-0B  | LEO | Success [13] | 
| 8 | May 19,2009 23:55  | TacSat-3 |   MARS LP-0B  | LEO | Success [14] | 
| 9 | February 6,2011 12:26  | USA-225 (NROL-66) |   Vandenberg SLC-8  | LEO | Success [15] | 
| 10 | June 30,2011 03:09  | ORS-1 |   MARS LP-0B  | LEO | Success [16] | 
| 11 | November 20,2013 01:15  | ORS-3, [17] STPSat-3 and 28 CubeSat satellites [18] |   MARS LP-0B  | LEO | Success [19] | 
| 12 | June 15,2021 13:35  | NROL-111 | MARS LP-0B | LEO | Success [20] | 
| 13 | June 18,2024 07:01  | Mk21A reentry vehicle test |   Vandenberg TP-01  | Suborbital | Success [21] |