Minuteman Missile - Abstract

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Converting the Minuteman Missile into a Small Satellite Launch System

Rodrick McHaty, et. all

November 24, 1993



Due to the Strategic Arms Reduction Talks (START) treaty between the United States and Ex-Soviet Union, 450 Minuteman II (MMII) missiles were recently taken out of service. Minotaur Designs Incorporated (MDI) intends to convert the MMII ballistic missile from a nuclear warhead carrier into a small-satellite launcher. MDI will perform this conversion by acquiring the Minuteman stages, purchasing currently available control wafers, and designing a new shroud and interfaces for the satellite. MDI is also responsible for properly integrating all systems.

System Description

Figure 1 shows a representation of the MDI missile. The stages that MDI will acquire from the Air Force are the MMII stage I and II, and the MMIII stage III. These stages define the propulsion system of the MDI missile, and an analysis of attainable orbits is performed. This analysis is also performed if the satellite customer requires a STAR 17A or STAR 27 injection stage.

Figure 1. MDI missile

The new MDI system still incorporates the original range-safety raceway and attitude-control actuators. MDI plans to purchase the 52 inch diameter avionics, range-safety, and attitude-control wafers from Martin Marietta's Multi-Service Launch System (MSLS), "D" configuration missile, which is currently under development.
MDI has designed a mechanical interface to the payload, that uses four truss elements and a Marmon clamp, which can wrap around various satellite diameters (see Figures 2 and 3). The support structure is able to support up to 1500 lbm. The payload support bulkhead has an allotted interface for any electrical connections the satellite requires. MDI has also sized a new shroud that fits various small satellites and uses a thrusting-joint-separation mechanism.

Figure 2: Support Structure

Figure 3: Payload Support Bulkhead and Marmon Clamp

MDI Missile Performance

The primary launch site is Vandenberg Air Force Base (VAFB) in California, and a secondary launch site is also available at Cape Canaveral Air Force Base in Florida. Combined, these two sites provide for a wide range of orbit inclinations (29 - 104). Figure 4 displays attainable orbits when the missile is launched from VAFB with various injection stages at permissible orbit inclinations. As the figure indicates, the MDI missile can launch payloads a big as 1000 lbm to circular orbits ranging from 100 to 2500 nautical miles (nm), depending on orbit inclination and what injection stage, if any, the customer wishes to use. The expected launch environments (temperatures, pressures, and vibrations) the satellite will be exposed to during launch are carefully studied and taken into consideration in the design of the MDI launch vehicle.

Figure 4: Attainable Orbits from VAFB

Mission Concepts

To stress the feasibility of its launch vehicle, MDI has performed two satellite mission designs as proof of concept. The two payloads chosen are BATSAT and the Asteroid Investigation Microspacecraft (AIM). Each payload has been properly interfaced with the missile, and MDI shows how the orbit needs are attainable with the launch system.

Launch System Competitiveness

To show launch system competitiveness, the MDI missile is compared to other small satellite launch systems (Scout and Pegasus). All systems have comparable attainable orbits, insertion errors, and usable shroud volumes. However, the MDI missile's launch costs ($7.5 million) are considerably less than the other launch systems ($12, $15 million)

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