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A Look at Minuteman Program

As associate prime contractor for guidance and control equipment for the MINUTEMAN ICBM, North American Aviation's Autonetics Division designed, developed, and is producing virtually all missile avionics. Autonetics systems integrated into MINUTEMAN for guidance and control comprise 99% of all electronics in the missile (except for the reentry vehicle). In addition to airborne systems, the division provides supporting aerospace automatic ground checkout and alinement equipment.

In fulfilling requirements of the MINUTEMAN I Program, Autonetics has met or surpassed goals of reliability, accuracy, and weight. Of the more than 25,000 components in its systems within each missile, over 98% achieved reliability improvement by a factor of 100 to 1. The program has established a record for the shortest development time from design to operation of any ballistic missile.

Technological requirements of the Ballistic Systems Division of the U.S. Air Force for the MINUTEMAN I missile were unprecedented at the outset of the program. The missile required a degree of reliability previously considered impossible. Design parameters called for extreme accuracy, storability, productivity, and low cost. The guidance and control systems were to be self-contained, jam-proof, and non-radiating. The requirement to fire from an underground silo in less than 60 seconds demanded subsystems and components of such long-term reliability that they could be left running for years without failure ready at any moment for launch to a target more than 6000 miles away.

To meet the challenge, Autonetics applied a concept of system simplification for the avionics design, and initiated a rigorous program of reliability improvement for components and systems. New engineering techniques and production methods were introduced, together with innovations in cost reduction and control. A separate MINUTEMAN Division was established to coordinate the activities of Autonetics, and of 35 major subcontractors and 3200 suppliers covering 40 states.

The overall technical key was integration-integration of Autonetics technical resources into the MINUTEMAN Division; and integration of multiple subsystems into a simplified, automatic, digital computer-controlled system which operates unattended.

Delivery was made of two complete wings the first year. The 300th unit-targeted for November 15, 1963 was delivered October 23, 1963. In August of 1964, the 1000th MINUTEMAN guidance system was delivered.

During the past 3 years of the MINUTEMAN I Program, Autonetics has held costs below the Ballistic Systems Division ceiling and/or target.

A look at Minuteman Scoreboard:

RELIABILITY

Guidance and Control (G&C)

Wing I: 70% higher than contract objective

Wing II-V: 60% higher than contract objective

(Wing II-V objective was 110% higher than Wing I objective)

Flight Control

Wing I: 900% higher than contract objective

Wing II-V: 360% higher than contract objective

(Wing II-V objective was 200% higher than Wing I objective)

Operational Ground Equipment

Wing I: 66% higher than contract objective

Wing II-V: 89% higher than contract objective

(Wing II-V objective was 135% higher than Wing I objective)

WEIGHT

Airborne Systems

15% below contract objective

ACCURACY

30% better than contract objective

FLIGHT TEST PROGRAM

Eastern Test Range (Cape Kennedy)

In 40 months: 53 Flights; 49 G&C Successes

Last 20 months: 35 Flights; No primary G&C failure

Western Test Range (Vandenberg AFB)

In 22 Months: 60 Flights; 57 G&C Successes

First 15 Months: 25 Flights; No primary G&C failure

EQUIPMENT DELIVERED

R&D 1,103 Pieces of End Item Equipment

Production 5,254 Pieces of End Item Equipment

16,357 Total in 34 Months

At Present 3 5 Major End Items shipped per working day

MINUTEMAN I DELIVERY

PERFORMANCE

Ahead of accelerated contract schedule

SITE OPERATION

In less than 22 months:

4 Complete Wings 600 Operational Sites

Over 6.4 million Gyro Operational Hours

Over 9.6 million Velocity Meter Operational Hours

PARTS OPERATION

Silo

25,505 Electronic Parts per silo

Over 60 billion Operational Parts Hours

Airborne

20,440 G&C Electronic Pprts per missile

Over 46 billion Operational Parts Hours

SPARES DELIVERED

Over 24,000 Line Items

Over 800,000 Parts

TRAINING

Over 500,000 Conducted Student Hours

A Look at MINUTEMAN II

AUTONETICS SYSTEMS FUNCTIONS IN MINUTEMAN II

Autonetics' new guidance and control system plays an expanded role in the MINUTEMAN II Weapon System, contributing substantially to the missile's increased range, accuracy, reliability, and strategic flexibility.

The heart of the system is an extremely fast, lightweight, microminiaturized D37 digital computer with a memory capable of storing a complete ground and airborne operational program, including all target data required for guidance to one of a number of stored targets. The desired target is selected remotely from a launch control center prior to missile launch.

PRELAUNCH: The computer, with the aid of Autonetics aerospace ground equipment, sequences the guidance and control system through alinement, test, calibration, and targeting modes into a strategic operating mode. During the strategic mode, the computer automatically decodes, processes, and executes commands from the launch control center for test, calibration, and targeting, and in addition continually monitors and reports missile and support equipment go/nogo status to the control center.

LAUNCH: When commanded to launch, the computer controls complete countdown in less than a minute in conjunction with the support equipment. Countdown includes complete testing of the missile system, activation of the missile battery power supplies, arming of the missile ordnance devices, initiation of flight program, and igniting of first-stage motor.

FLIGHT After ignition of the first stage, the computer processes missile attitude, attitude rate, and velocity information from stable platform position pickoffs, downstage angular accelerometers, and platform accelerometers, to solve guidance, steering, and control equations. Moveable nozzles on first and third stages, and liquid injection on second stage, control the direction of thrust for missile steering. Nozzle movements and liquid injection are commanded by the computer and mechanized by the flight control system. The computer also generates signals for staging, third stage thrust termination, and warhead pre-arming, as well as re-entry vehicle separation, retro-rocket firing, and penetration aids dispersal. Pre-arming of the warhead follows flight safety checks made during final moments of powered flight.

A Look at...

ADVANCES IN MINUTEMAN II ELECTRONIC SYSTEMS THROUGH USE OF MICROELECTRONICS

Technical advances by Autoneties in microelectronics are being incorporated into the MINUTEMAN 11, to achieve even greater dependability of the missile, increased system flexibility, lighter weight for extended range, and ultimately lower cost. For this improved version of the missile, Autoneties developed the first microelectronic equipment ever pro. vided for a major defense program.

COMPUTER ADVANCES: Autonetics' D 37 computer in MINUTEMAN II is the first military production-designed microelectronic computer. Size of the D37 is one-fourth that of its D17 predecessor in MINUTEMAN I. Weight has been reduced by one-half, and power requirements are one-half. Memory capacity has increased by 2 1/2 times. The power supply has been incorporated into the computer. In addition, many of the previous ground checkout equipment functions are performed by the new microelectronic computer.

The D37 is mechanized by integrated circuits. Multilayer circuit boards, on which the microelectronic circuits are mounted, provide for high packing densities, improve the interconnection techniques, and permit easy maintenance.

GROUND EQUIPMENT ADVANCES: Use of microelectronic circuits has reduced both size and weight of MINUTEMAN ground equipment and increased its operational flexibility. Equipment for MINUTEMAN I, which consisted of a two-bay console housed in a targeting van, has been miniaturized to the size of two small suitcases for MINUTEMAN II. Weight has dropped from 950 lb to 90 lb – or to just 45-lb one-man carry" weight for each of the two suitcases.

INERTIAL PLATFORM ADVANCES: The MINUTEMAN II uses a three-axis, gyro-stabilized platform which mounts three pendulous integrating gyro accelerometers and a gyrocompass azimuth assembly. The platform includes extensive microelectronics and is of conventional external-gimbal design with beryllium gimbals and a beryllium stable element. Ruggedness and extreme rigidity are primary characteristics.

The stable platform is mounted within a pressurized housing which contains a water-to-gas heat exchanger for precise temperature control.

FLIGHT CONTROL ADVANCES: Microelectronics incorporated into Autonetics' flight control subsystem in the MINUTEMAN II contributes to the missile's lighter weight, increased reliability, and reduced field maintenance costs.

The use of integrated circuits and microminiaturized components allows the major portion of flight control electronics to be packaged into a single unit and moved upstage into the guidance and control package of MINUTEMAN II. Because this guidance and control section can be replaced in the silo without removing the missile, field maintenance has been considerably simplified.

A new attitude control group (secondary injection system) with microelectronic components governs injection of liquid Freon to the second stage nozzle control unit.