From Bombs to Rockets at McGregor, Texas

Transcription

1 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition 5-8 January 2009, Orlando, Florida AIAA From Bombs to Rockets at McGregor, Texas Thomas L. Moore 1 ATK Tactical Propulsion and Controls, Baltimore, Maryland, USA Hugh J. McSpadden 2 Universal Propulsion Company (retired), Phoenix, Arizona, USA McGregor, Texas, is the location of a former World War II-era bomb loading plant, named the Bluebonnet Ordnance Plant, which was later converted to a facility for the production of ammonium nitrate composite solid rocket propellants and aircraft jet-assist takeoff (JATO) units for the Air Force. Under successive operating contractors Phillips Petroleum Company ( ), Astrodyne Incorporated ( ), Rocketdyne ( ), and Hercules Incorporated ( ), the McGregor plant expanded into the tactical propulsion market and, using its signature Flexadyne series of CTPB propellants, manufactured rocket motors for air-launched missiles such as Sparrow, Shrike, AIM-9C/D Sidewinder, and Phoenix. By the 1980s, McGregor developed the capability to produce HTPB reduced smoke propellants for AMRAAM, HARM, AIM-9L/M Sidewinder, the Rolling Airframe Missile (RAM) and the AGM-130 rocket motor, as well as advanced techniques for manufacturing precision metal parts and rocket motor cases. In June 1994, Hercules announced its intent to cease operations at the McGregor plant and transfer its remaining active tactical production programs to Allegany Ballistics Laboratory in Rocket Center, West Virginia. This transition was completed in 1996 by Alliant Techsystems, which had purchased Hercules aerospace business in March Following a Government assessment, environmental cleanup, and Congressional action, the abandoned plant property was conveyed to the City of McGregor for the purpose of economic development. The history, technical achievements, major products, and notable events and milestones from the long history of the McGregor solid propulsion plant are described. I I. Railroads Give Birth to McGregor, Texas N central Texas, 15 miles southwest of Waco, lies the small town of McGregor (2000 population of 4,727). The settling of McGregor began in 1879, when two growing railroads, the north-south Santa Fe and the east-west Cotton Belt, intersected their rail lines at this geographic point on the Texas prairie, offering a natural point for a railway stop and a place for the steam trains to refill with water. A land sale for lots in the town of McGregor Springs, as it was first known, was held on 7 September The town was named for Dr. Gregor Carmichael McGregor, a pioneer Texas physician who provided railroad right-of-way across his land and later became a prominent Waco businessman. The town became incorporated as the City of McGregor in McGregor subsisted largely on railroad commerce and agriculture throughout the late 1800s and early 1900s. The area s fertile black soil and abundant rainfall yielded primary crops of wheat, oats, corn, and cotton. Range grass also provided an ample food supply for herds of longhorn cattle that were driven north to market. 1 The town grew in population from about 800 in the late 1800s to just over 2,000 by However, as a result of World War II, this quiet agricultural community would experience a radical change. II. The Bluebonnet Ordnance Plant (B.O.P.) is Established The entry of the United States into World War II signaled a critical and immediate need for increased domestic production of ammunition, bombs, and other ordnance. As a result, the U.S. Government rapidly constructed munitions-producing plants around the country, negotiating contracts with industrial companies to staff the plants 1 Sr. Staff Engineer, 1501 S. Clinton St. 11 th Floor, Baltimore, MD 21224; Associate Fellow AIAA W. Hartford Avenue, Glendale, AZ 85308, Senior Member AIAA (retired). Approved for public release per OSR Case No. 08-S Copyright 2009 by Alliant Techsystems Inc. Published by the, Inc., with permission.

2 and conduct wartime ordnance manufacturing operations. One such plant, the Bluebonnet Ordnance Plant (B.O.P.), was established in 1942 on the southwest side of McGregor. Like many other companies of the era, the National Gypsum Company of Buffalo, New York sought to participate in the burgeoning war industry. On 9 February 1942, after successfully lobbying War Department officials, the company signed a contract with the Army Ordnance Command in Washington, DC to build and operate a new munitions plant on 18,000+ acres purchased by the U.S. Government in McLennan County, Texas with a small western portion of property in Coryell County. Temporary offices were soon set up in Waco and McGregor, and ground was broken for the new plant on 18 April Four months later, administrative offices on the plant site were occupied, and the first production of bombs began on Line 1 on 16 October In just a few short months, McGregor s population swelled to over 6,000 people. As was customary with contractor-operated munitions plants of the time, the Bluebonnet Ordnance Plant had a military presence in the form of a commander, his staff, and a security force. B.O.P. s first commanding officer is credited with naming the plant after the Texas state flower. Bluebonnet was like a city unto itself, complete with living quarters, security and fire protection services, stores, merchants, entertainment venues, bus service, and a regular plant newspaper. Top officials and managers were required to be on call 24 hours a day and lived on the B.O.P. reservation. Three types of bombs were loaded at Bluebonnet, ranging in size from 100 lb to 2000 lb. They included Semi-armor Piercing (SAP), General Purpose (GP), and Fragmentation Bombs. While the SAP and GP were conventional bombs used against ships and/or structures, the Fragmentation (or Parachute) Bomb was quite different. This 23-lb bomb, shown in Fig. 1, was a small, lightweight bomb used against personnel and planes on the ground. It could be dropped individually or in clusters. Bomb Lines 2 and 3, as well as the booster line and ammonium nitrate plant, were built and activated at Bluebonnet by the end of All of the bomb lines were identical, operating three shifts around the clock to produce all three types of bombs. Production schedules and volume were constantly changing, and some of the lines would switch products to be loaded or even shut down for brief periods of time. Production of ammonium nitrate for ordnance applications began on 7 December 1942 and concluded the following June. In August 1943, the ammonium nitrate plant was reactivated to produce fertilizer, which it did for another year before it was shut down. A fourth bomb line with increased capacity and an improved building arrangement was opened in February 1945 and produced only 500-lb GP bombs. Figure 1. Parachute bomb. Bluebonnet also produced other ordnance products, including 105-mm semi-fixed high explosive shells, bomb booster charges, and demolition blocks shown in Figs. 2, 3, and 4, respectively. The explosive melt-pour building is shown in Fig. 5. Unlike the bomb lines (Figs. 6 and 7), the booster line (Figs. 8 and 9) operated only five or six days per week. Figure mm shell. Figure 3. Booster charges. Figure 4. Packaged demolition blocks. Credit all photos this page: The Texas Collection, Baylor University, Waco, Texas 2

3 Figure 5. Melt-pour building (note emergency escape slides). Figure 6. Bomb loading preparation. Figure 7. Bomb inspection. Figure 8. Booster processing. Figure 9. Exterior view of booster line. Credit all photos this page: The Texas Collection, Baylor University, Waco, Texas 3

4 One of the highlights of the rather brief life of the Bluebonnet Ordnance Plant was the 27 October 1944 presentation of the Army-Navy E Award to the plant for outstanding performance in war production. A display of B.O.P. products on E day is shown in Fig. 10. Upon the cessation of production operations on 14 August 1945, Bluebonnet laid claim to the production of over 4 million bombs and nearly 9 million ordnance items. The final Bluebonnet production statistics are presented in Table 1. Figure 10. Bluebonnet products on display on E day. Credit: The Texas Collection, Baylor University, Waco, Texas Table 1. Bluebonnet Ordnance Plant production history. 2 Item Quantity Item Quantity 105 mm shell 886, lb GP 122,040 Booster, M102 & M102A1 3,325, lb, T1 450,065 Booster, M104 4,249, lb SAP 21,959 Booster, M115 92, lb GP (TNT) 175,142 Booster, T3 55, lb GP (Comp B) 589,369 Demolition Blocks (units of 8) 193, lb GP (Tritonal) 507,164 Fragmentation Bomb, M72 345, lb SAP 324,624 Fragmentation Bomb w/o parachute 317, lb GP (TNT) 7,526 Fragmentation Bomb Cluster, M1 563, lb GP (Tritonal) 7,367 Fragmentation Bomb Cluster, M4 566, lb SAP (Picratol) 2,558 Fragmentation Bomb Conversion Kit 734, lb GP (Picratol) 6 Ammonium nitrate 46,307 tons Tetryl pellets 215,402 lb 4

5 On 30 November 1945, the last cafeterias and dormitories at Bluebonnet were closed, and the plant was turned over to the Army Ordnance Department for post-war disposition. An inter-government agency transfer of the plant from the War Department to the War Assets Administration occurred on 16 April Following its closure, portions of the plant were converted to peacetime uses, including stove and furniture manufacturing, and some of the land was sold to individuals. The largest portion, 17,483 acres, was conveyed to Texas A&M University to establish an experimental farm and research center initially named the Bluebonnet Farm. The Government retained a 20-year recapture provision on the conveyance to Texas A&M. III. Air Force Claims McGregor Site for JATO Production The Phillips Petroleum Company, long associated with its Phillips 66 gasoline trademark, was one of several companies involved in solid propellant research in the United States in the 1950s. In 1951, Phillips established its Rocket Fuels Division, conducting research and development of composite propellants at laboratory facilities in Bartlesville, Oklahoma. Phillips research generated Air Force interest in solid propellant jet-assisted take-off (JATO) devices, a type of solid propellant rocket externally attached to aircraft in various quantities to provide additional take-off thrust for heavily loaded planes or take-off from very short runways. Under Air Force contract, Phillips generated detailed plans for the establishment of a pilot plant to further develop and produce its propellants for JATO applications. In mid-1952, following a survey of war surplus plants and airfields in Oklahoma and Texas, the Air Force selected the former Bluebonnet Ordnance Plant as the location for a solid propellant pilot plant and manufacturing facility to be operated by Phillips. The Air Force executed the U.S. Government s postwar recapture provision to acquire about 11,450 acres of the former Bluebonnet Ordnance Plant and reactivate it as Air Force Plant No. 66. Texas A&M retained a southern 6,372-acre parcel of the former B.O.P. where it continues to operate its McGregor Research Center to this day. On 1 August 1952, Phillips was awarded an Air Force contract to complete the design of the plant and establish manufacturing capacity for solid propellant JATOs at McGregor. 3 The Governmentowned, contractor-operated (GOCO) plant became part of Phillips Rocket Fuels Division. Temporary pilot plant operations were established on the former Bomb Line No. 4 (named Area M by Phillips), while construction of the permanent pilot plant took place on the site of the former booster production line (Area F). The first live propellant was processed at McGregor on 11 November After the completion of the permanent pilot plant, Area M was converted to production use. By 1956, over 30 new buildings were constructed to support solid propellant research and development, manufacturing, and testing. With the installation of two production-scale propellant mixers, Area M became the first solid propellant manufacturing line for the large-scale production of JATOs 5 at McGregor. The plant reached a peak employment of 1,300 by 1955, providing a more controlled economic boost for the rural McGregor area than that which had occurred in Phillips was one of two U.S. companies (the other being B. F. Goodrich Company) that conducted early research on the use of butadiene-based synthetic rubber as binders for composite rocket propellants. Phillips developed propellants based on ammonium nitrate (AN) oxidizer and a copolymer consisting of 90% butadiene and 10% 2-methyl-5-vinylpyridine (Bd-MVP). 6 As a product of the synthesis of petroleum refinery gas, butadiene was readily available in large quantities for composite propellant production. Phillips research led to the successful development of a 16-second, 1000-lbf thrust JATO unit for the Air Force between 1953 and This JATO was originally given the designation T60 under the Ordnance Nomenclature System used prior to 1962 and, upon qualification, became the M15 (the A1 suffix denotes the first service-approved modification of the production model). 7 As shown in Fig. 11, the M15A1 JATO was essentially a welded steel tank with open aft end to accommodate a cartridge-loaded grain and closure (hence, the nickname JATO bottle ). The AN/Bd-MVP propellant grain burned on all sides, producing an average thrust of about 1,020 lbf over a 16-second burn time at 60 F. Several difficulties were encountered during the original qualification of the T60/M15 JATO, including lack of ballistic performance reproducibility. Phillips subsequently investigated minor changes to its early AN/Bd-MVP propellant formulations, replacing a vulcanizing system (sulfur, SA-113, and zinc oxide) used in early formulations with a Milori Blue/magnesium oxide cure system. This resulted in improvements in aging properties, processing characteristics, and ballistic reproducibility of the JATO propellant. The typical composition of a qualified Phillips AN/Bd-MVP composite propellant is found in Table 2. 8 In 2002, Phillips Petroleum Company merged with Conoco Oil Company to form ConocoPhillips. 5

6 Figure NS-1000 (M15A1) JATO manufactured at McGregor. Table 2. Phillips Formulation PPC-127 (later RDS-127). Ingredient Function Weight % Ammonium nitrate Oxidizer Bd-MVP copolymer Binder Ferric ammonium ferrocyanide (Milori Blue) Burning rate catalyst 1.95 Flexamine Rubber antioxidant 0.33 Carbon black (Philblack A) Reinforcing agent 2.49 Butyl carbitol formal (ZP-211) Plasticizer 2.22 Magnesium oxide Curing agent 0.49 TOTAL Flexamine is a physical mixture consisting of 35% N,N'-diphenyl-1,4-phenylenediamine and 65% of a complex diarylamine-ketone reaction product (Naugatuck Chemical Division of the U.S. Rubber Company). 6

7 Successful qualification tests on the improved M15 JATO design took place from June to October 1955, and the unit was released for mass production. Production of the M15A1 lasted for more than two decades and eventually reached over 150,000 units delivered. It was used in varying quantities on many aircraft, including the B-47, B-66, C-47, C-130A/B/BL, C-133, F-84, F-94, HC-47, HU-16A/B/C, LC-130F, P2E, P2H, V-5, V-7, P-5A/B, RB-66, T- 33, and the UF-1 series. Unfortunately, early Air Force procurement requirements for JATO units failed to support the size of the 1955 workforce at McGregor, and employment subsequently dropped to about 750 for the remainder of the decade. In 1958, North American Aviation, which itself had been involved with research in solid propellant air-to-air rockets as early as 1951 at its Rocketdyne Division in California, entered into a partnership with Phillips to form Astrodyne Incorporated. Astrodyne assumed the management and operation of Air Force Plant 66, using many of the same employees from Phillips Rocket Fuels Division. The injection of additional assets and capital from the partnership proved fruitful, as Astrodyne began a long-range program to modernize McGregor s facilities and expand its research capability in solid propellant rocketry and related hardware. On 30 September 1959, North American Aviation purchased Phillips share of Astrodyne and the plant became Rocketdyne s Solid Propulsion Operations. 1 North American s full ownership provided the opportunity for an infusion of additional technical and managerial talent from the company s operations in California. As shown in Fig. 12, signage on the McGregor plant headquarters, known as Building A-101, bears the new name. In the late 1950s and 1960s, the McGregor plant also specialized in the development and production of ammonium nitrate-based solid propellant gas generators for various applications. Two such units, designated the Mk 2 and Mk 3, were manufactured for the Navy s early Terrier and Tartar missiles. 9 These gas generators were paired in each missile to initiate turbine spin for electrical and hydraulic power supply. Another was developed to eject payloads from the linear bomb bay of the A3J supersonic attack bomber. Still another McGregor-produced unit provided power to start the turbopumps of the Rocketdyneproduced H-I liquid rocket engine for NASA s Saturn 1 launch vehicle. A modification of the H-I engine starter was also adapted for use with the Atlas MA-3 rocket engine. McGregor also produced thousands of gas generator starter cartridges for jet engine aircraft. Figure 13. Zero-Length F-100 launch. Figure 12. Rocketdyne McGregor headquarters, circa Credit: Rocketdyne One of the more interesting formerly classified products developed and built at McGregor in the late 1950s was the humanrated M34 Zero Length (ZEL) motor designed to launch and accelerate the F-100 Super Sabre jet fighter from a fixed semitrailer or other rigid support (Fig. 13). The ZEL motor was 27.2 inches in diameter, feet long, and provided a takeoff thrust of 130,000 lbf for 4 seconds, accelerating the aircraft to 275 miles per hour and 4 g before separating and dropping away from the jet. The ZEL motor represented a major scaleup in size from what had been produced to date at McGregor. Although the ZEL motor was not adopted for regular service use due to safety, cost, and logistics concerns, the motor design served as the baseline from which a number of derivatives emerged, including a canted nozzle version used in pairs as JATOs for the RGM-15 Regulus II cruise missile, a 330,000-lbf magnum version, and the longer burning (10 second) Megaboom which provided 100,000 lbf of thrust for sled track rockets. 7

8 McGregor also made other contributions to the U.S. manned space program of the 1960s and 1970s. It developed and produced ullage motors for NASA s Saturn V space launch vehicle. Ullage motors were used to momentarily accelerate the S-II second stage forward after first stage burnout, ensuring that the liquid propellant was in proper position for ignition of the second stage engines. 10 IV. Rocketdyne Expands into Navy Tactical Market As the Rocketdyne Solid Rocket Division, McGregor continued to leverage Phillips early work in composite propellant development and was soon developing and producing many of the conventional rubbery binder-based composite propellant formulations of the period. Rocketdyne began the production of propellants using ammonium perchlorate oxidizer in a carboxyl-terminated polybutadiene (CTPB) binder in Based upon Phillips Butarez CTL pre-polymer produced in Borger, Texas, ** Rocketdyne s CTPB propellants were marketed under the trade name Flexadyne and were known for retaining excellent mechanical properties over a very wide temperature range. This led to Rocketdyne McGregor s entry into the modern air-launched tactical propulsion market which required propellants that could withstand a temperature range as great as -70 F to +170 F. 12 Rocketdyne propellants were assigned a numerical designation preceded by the letters RDS, for Rocketdyne Solid. Table 3 defines the Rocketdyne solid propellant nomenclature. The RDS-500 family of Flexadyne propellants soon became the dominant product of the McGregor plant, used in rocket motors for Sparrow III, Sidewinder 1A, Shrike, and Phoenix missiles. Table 3. Rocketdyne propellant nomenclature. Series RDS-100 through RDS-299 (PPC prefix under Phillips) RDS-3xx series RDS-4xx series RDS-5xx series RDS-8xx series (later MG-8xx under Hercules) Type Propellant Extrudable and castable ammonium nitrate (AN) and extrudable ammonium perchlorate (AP) formulations Castable propellants containing AP and a polyurethane binder Castable propellants containing AP and a polybutadiene-acrylic acid binder Castable propellants containing AP and a carboxyl-terminated polybutadiene (CTPB) binder (also known as the Flexadyne family of propellants) Castable propellants containing AP and a hydroxyl-terminated polybutadiene (HTPB) binder; may or may not contain aluminum fuel By October 1964, the majority of the work being performed at McGregor was for U.S. Navy programs, so the Air Force agreed to transfer ownership and oversight of the facility to the Navy. On 1 May 1966, the land, equipment and other Government-owned assets of the McGregor plant were transferred to the Navy, and Air Force Plant No. 66 became a Naval Industrial Ordnance Plant under the cognizance of the Naval Ordnance Systems Command (NAVORD). In 1967, when North American Aviation and Rockwell merged, Rocketdyne became a division of North American Rockwell Corporation, which then became Rockwell International in By this time, the facility was designated a Naval Weapons Industrial Reserve Plant (NWIRP) under the cognizance of the Naval Air Systems Command (NAVAIR). 13 A map of NWIRP McGregor, shown in Fig. 14, depicts the layout of the various administrative, production, trades, and storage areas that remained largely unchanged from the late 1960s until the 1990s. Areas L and M were the original B.O.P. bomb lines 3 and 4, respectively. After the activation of Air Force Plant 66, Area M (Fig. 15) became the main propellant and motor manufacturing and inspection area, and Area L (Fig. 16) was converted over to testing with the construction of a new large motor static test stand (Bldg. 1140) in The original 40,000-sq ft E-shaped administration building, designated A-101, was located in Area A at 1101 Johnson Drive. In 1967, a new 50,000-sq ft administration building, designated A-100 (Fig. 17), was built directly in front of A-101, which was later demolished and removed. Area H, the northern bunker field, originally contained 118 World War II-era ** Production of Butarez ceased after a July 1996 fire at the Phillips facility. 8

9 explosive storage bunkers. About 25% of those were removed by 1995 due to structural damage or poor condition. Area D (Fig. 18) housed machine shops and metalworking facilities that produced rocket motor cases, tooling, and other metal parts. By 1987, McGregor installed advanced Leifeld flow forming equipment in Area E for the high rate production of metal rocket motor cases. The materials and propellant research and pilot plant facility was located in Area F (Fig. 19), while Area R (Fig. 20) served as the small rocket static test area. The conspicuous square notch of land between Area E and FM (Farm-to-Market Road) 2671 was part of 1,600 acres of former plant Areas J, K, and N that were transferred to private entities in April Areas J and K, clearly shown in Fig. 21, were the original locations of World War II bomb lines 1 and 2. Note the consistent offset distance between the four original bomb loading areas. Area N, a B.O.P.-era southern bunker field consisting of 102 high explosive storage units located immediately south of former Areas J and K, became part of the larger Texas A&M Research Center that adjoins the southern boundary of the McGregor plant. Figure 14. NWIRP McGregor plant map, circa

10 Figure 15. Area M, Motor Manufacturing and X-ray. Figure 16. Area L, Large Motor Static Test. Figure 17. A-100 Administration and Engineering. Figure 18. Area D, Machine Shops. Figure 19. Area F, Materials and Propellant Labs, Airbreathing Test, and AUR Missile Assembly. Figure 20. Area R, Environmental and Small Motor Static Test. 10

11 Figure 21. NWIRP McGregor and surrounding area, circa From the late 1950s through the 1960s, most composite solid propellants manufactured in the United States consisted mainly of ammonium perchlorate, aluminum powder, and other minor constituents dispersed in an inert binder (polysulfide, polyurethane, or polybutadiene). The decade of the 1970s brought about the next significant advance in composite propellants: the maturation of formulations based on hydroxyl-terminated polybutadiene (HTPB) binder. HTPB propellants gained a performance edge over predecessor composite formulations by allowing higher solids loadings and greater aluminum content. By the 1980s, HTPB supplanted CTPB and other binder types as the formulation of choice for many tactical missile systems. 15 While the addition of large amounts of aluminum (15 to 20% by weight) to composite propellants was one of the early enabling technologies for high performance solid rocket motors, 16,17 the byproduct of their operation is a highly visible exhaust contrail. By the mid-1970s, McGregor joined other organizations of the period (Aerojet, Atlantic Research Corporation, Thiokol, and Allegany Ballistics Laboratory) in the development of reduced smoke HTPB propellants for air-launched tactical missile applications. The visible exhaust signature of motors containing composite propellant was greatly reduced by eliminating aluminum from the formulation, making the missile less vulnerable to detection and neutralization. McGregor s capability in reduced smoke propellants ensured its involvement in the next generation of air-launched tactical missiles. McGregor subsequently produced reduced smoke AP/HTPB propellants for Sidewinder, AIM-120 AMRAAM, the AGM-130 rocket motor for the GBU-15 glide bomb, and for the ship-launched Rolling Airframe Missile (RAM). McGregor s reduced smoke propellants contained solids loadings of 86 to 88% and were reportedly tailorable to a burning rate range of 0.25 in/sec to more than 1.0 in/sec. 11

12 V. Hercules Assumes Operating Responsibility for McGregor In the late 1970s, Rockwell International began a series of divestitures and spin-offs that included the operation of the McGregor plant. In January 1978, operating responsibility for McGregor was turned over to Hercules Incorporated, a legacy provider of solid propulsion systems since the 1940s, which already operated plants in Rocket Center, West Virginia, and Magna, Utah. Hercules retained the McGregor workforce, and the production of tactical rocket motors, gas generators, and JATOs for the U.S. Government continued without interruption. Average employment during Hercules management of McGregor was about 460 people. In 1979, Hercules began the full-scale development (FSD) of a reduced smoke rocket motor for the AIM-120 Advanced Medium Range Air-to-Air Missile (AMRAAM) under contract to Hughes Aircraft Company. The AMRAAM motor, shown in Fig. 22, featured a single case bonded propellant grain designed to provide a boostsustain thrust profile, an electromechanical arm/fire device, flow formed case, and high performance blast tube and exit cone. A 45-motor qualification program was conducted in 1985 and final preflight readiness test (PFRT) deliveries were completed in In the late 1980s, competitor Aerojet also developed and produced its own version of the AMRAAM rocket motor for co-prime contractor Raytheon in Massachusetts. Following Raytheon s purchase of Hughes Aircraft Company in 1997, AMRAAM missile production was consolidated to Tucson, Arizona, and ATK became the sole supplier of AMRAAM rocket motors. Figure 22. AMRAAM WPU-6/B rocket motor developed at McGregor. In 1981, Hercules McGregor expanded its role in the tactical missile business by its selection as the all-upround (AUR) assembly contractor for the AGM-88A/B High-speed Anti-Radiation Missile (HARM), shown in Fig. 23. Under contract to Texas Instruments, who served as the HARM weapon system integration contractor, workers at the McGregor plant assembled the guidance, warhead, control, and rocket motor sections that were supplied as Government-furnished equipment (GFE). Beginning in 1984, HARM AUR missile assembly was competitively procured with Thiokol s Wasatch Division in northern Utah (now ATK Space Systems Promontory campus). McGregor assembled a total of about 14,500 HARM missiles between 1981 and The reduced-smoke propellant rocket motor for HARM, designated YSR113-TC-1, was originally developed by Thiokol in Utah in the late 1970s. In 1986, Hercules McGregor was successfully qualified as a second-source supplier for the HARM rocket motor, sharing production responsibilities with Thiokol for the next 10 years. Between 1986 and 1995, Hercules manufactured about 11,000 HARM motors to the Thiokol design specifications, a quantity roughly equivalent to the Thiokol population of motors. McGregor also qualified its process for manufacturing D6aC steel HARM cases using its resident capability in the flow forming of cylindrical steel sections, CNC machining, electron beam welding, and TIG welding. In the early 1990s, about 800 Hercules-manufactured HARM motors were removed from service as a result of defects found in Figure 23. HARM missile assembly. cold x-ray screening. These were replaced by Thiokol-remanufactured units. Hughes Aircraft Company was purchased by Raytheon in

13 In August 1992, Hercules made its final delivery of the Mk 47 Phoenix rocket motor (Fig. 24), ending 24 years of continuous production at McGregor. At the time, the AIM-54 Phoenix was the Navy s only allweather long range air-to-air system designed to defeat multiple targets in the performance of naval fleet air defense. A Figure 24. Phoenix rocket motor. maximum of six missiles could be carried on the F-14 aircraft, with the capability of launching simultaneously against six different targets. 18 Phoenix production helped to provide McGregor with a stable production base over its last two decades of operation. McGregor also produced rocket motors for other non-weapon applications. In the early 1970s, McGregor developed, qualified, and produced a high-burning rate, 19-inch diameter spherical motor (Fig. 25) that was to be used to provide ejection and maneuvering thrust for the B-1A bomber aircrew escape module. The human-rated motor featured a high surface area boost-sustain grain design and aluminized CTPB propellant to produce more than 44,000 lbf of thrust in less than two seconds. However, the B-1A program switched from the single aircrew module to more conventional individual crew ejection seats to reduce cost and weight, and McGregor s B-1 Escape Capsule Rocket Motor was not used in the final configuration. Figure 25. B-1 Escape Capsule Rocket Motor and nozzle-up static test. VI. Airbreathing Propulsion Endeavors McGregor s work in variable geometry nozzles (VGNs) for liquid-fueled ramjets in the mid-1970s provided the path for Rocketdyne s (and later, Hercules ) entry into the airbreathing propulsion arena. Under contract F C-2046 with the Air Force Aero Propulsion Laboratory (AFAPL) at Wright-Patterson Air Force Base, Ohio, McGregor designed, analyzed, and built a full-scale 18-inch diameter multi-position VGN. As part of the program, three heavyweight and two flightweight VGN/ramburner configurations were tested at Marquardt Corporation facilities in California. The nozzle/ramburner configurations were tested over a broad range of operating conditions to simulate ramjet takeover, acceleration, and cruise flight conditions that were consistent with advanced missile requirements. This program also introduced the use of silica phenolic as a standard ramjet nozzle liner/throat material. In 1976, McGregor was selected to be part of the Martin Marietta/Marquardt/Rocketdyne team that was awarded a contract to demonstrate an integral rocket ramjet (IRR) design for the Air Force s Advanced Strategic Air Launched Missile Propulsion Technology Validation (ASALM-PTV) program. Another team comprised of McDonnell Douglas and United Technologies Chemical Systems Division (CSD) was also awarded a competing ASALM-PTV contract. The Martin Marietta-led team accomplished a highly successful seven flight test program in 1979 and As McGregor continued with company-funded studies of candidate fuels and design approaches for ducted rockets, 20,21 Hercules was awarded an Air Force contract (F C-2005) in December 1979 for the development of variable flow ducted rocket (VFDR) technology. Under this contract, Hercules successfully developed a flightweight solid fuel gas generator (including an end-burning fuel grain, vented stress-relieving liner (SRL), thermal protection system, and mechanical retention system), a throttle control system (TCS), and a flight- 13

14 type ramburner. A total of 11 static variable flow gas generator firings and 5 direct-connect engine firings were conducted at McGregor s new airbreathing test facility located in Area F. McGregor established its low cost, clean air direct-connect airbreathing propulsion test facility to permit on-site testing and rapid turnaround of data. The facility was not built to perform complete boost-sustain ramjet engine firings, but could simulate sustain phase engine operation for durations from a few seconds to 60 seconds or more. The McGregor facility contained two pebble bed heaters and was capable of regulating air flow during a test from about 4 to 22 pounds per second. A typical test would simulate a 35,000-ft altitude launch at Mach 1.8 and climb out to 70,000 feet and Mach 4. A steam ejector was used to simulate altitude back pressures. McGregor s technological advancements were incorporated into a follow-on contract (F C-2300) awarded in 1983 to further develop gas generator fuels and a throttle control system for VFDR applications. Propellant throttleability was demonstrated in subscale and full-scale generator tests. During Phase II of the contract, vibration testing of a flightweight throttled gas generator, throttled static firings, generator-combustor interface direct-connect tests, and engine performance demonstration direct-connect tests were conducted. In 1987, Hercules (HI) and Atlantic Research Corporation (ARC) formed a joint venture to execute yet another Air Force contract (F C-2700) for a flight ready system level demonstration of VFDR technology that could be integrated with the AMRAAM forebody. The HI/ARC VFDR design is shown in Fig. 26. Hercules had lead responsibility for the solid fuel gas generator and propellant, booster/combustor case fabrication, fuel delivery system (including throttle valve hardware and control logic), and the arm/fire device, while ARC was responsible for the nozzleless booster grain, inlets and port cover, and engine integration and testing. Solid Fuel Gas Generator Integral Booster/Combustor Air Inlets Fuel Control System Figure 26. VFDR inboard profile. 23 Under this program, McGregor developed the gas generator and throttle valve which were successfully demonstrated in component level environmental tests (vibration, shock, temperature shock, and aeroheating). A total of 16 flight design gas generators were built at McGregor. Five were static tested and 4 were fired in engine tests at the McGregor facility. Combustion performance of the gas generator met or exceeded design requirements. Four gas generators were later fired in engine tests at ARC. During the early phase of this program, McGregor also conducted approximately 24 direct-connect engine firings under the Flame Stabilization and Piloting (FSAP) test series to optimize engine takeover and fuel injection design for ramburner piloting and performance. The original 5-year program schedule was eventually extended to 10 years due to funding issues, changing requirements, and technical difficulties. The HI/ARC (later ATK/ARC) Joint Venture did, however, make significant progress toward flightweight component level demonstration. 22 In 1997, the program concluded with two successful full-system boost-to-sustain transition ground tests of VFDR flight-ready hardware at ARC. 23 VII. Defense Downturn and Deactivation By the early 1990s, the downturn in U.S. defense spending created an overcapacity in the tactical propulsion industrial market. McGregor s product portfolio was reduced in size as the final deliveries for Mk 25 JATO and Phoenix motors were completed, contracts for Hercules production of HARM and RAM motors concluded, and the Sea Lance anti-submarine missile development program was cancelled. By 1994, the plant was subsisting on little more than the production of AMRAAM, AGM-130, and Sidewinder. Meanwhile, Hercules other tactical propulsion plant, Allegany Ballistics Laboratory (ABL) in Rocket Center, West Virginia, was engaged in the early part of a massive facilities restoration program funded by the DoD. Owned by the Naval Sea Systems Command (NAVSEA) and operated by Hercules since 1946, ABL had developed and produced tactical rocket motors for the AIM-7F Sparrow air-to-air missile, BGM-71 TOW-2 anti-tank missile, AGM-114B+ Hellfire air-to-ground missile, and AIM-9P Sidewinder, as well as the second stage of the first 14

15 generation Polaris submarine-launched ballistic missile, high performance stages for the Sprint interceptor missile, and launch eject gas generators. The DoD-funded restoration program provided a sorely needed upgrade of ABL s World War II-era facilities. Like McGregor, ABL had its origins as a wartime ordnance production plant. 24 Recognizing that its tactical propulsion requirements could be accomplished by a single facility, Hercules announced the closure of the McGregor plant in June 1994 and the consolidation of its remaining tactical rocket motor programs to ABL. Over the next year, active production programs for the AGM-130 and AMRAAM were successfully transitioned and qualified at ABL. In addition, McGregor s state-of-the-art metalworking and forming equipment used to make rocket motor cases and other components was moved to Rocket Center, along with a number of skilled machine shop operators. Although McGregor s active rocket motor production programs moved to ABL, few other employees were transferred and most left the business to retire or find jobs elsewhere. In March 1995, Hercules Incorporated, in its quest to become a smaller company based upon its core chemicals and resins product lines, sold its aerospace business to Alliant Techsystems (ATK) of Hopkins, Minnesota. ATK continued drawdown and closeout activities at the McGregor site until 31 July 1996, when the last employee locked the doors of A-100 and drove off the plant for good, ending another long and proud chapter in the history of the U.S. solid rocket industry. In its 44-year history as a solid rocket plant, McGregor had produced over 300,000 rocket motors and related products for the DoD and NASA, and for military and civil aircraft applications. A tabulation of major products produced at McGregor is presented in Table 4. Table 4. Major propulsion-related products manufactured by the McGregor plant. Motor Missile System ID Use No. Made Dates AGM-130 GBU-15 Auxiliary boost Transferred to ABL. AMRAAM WPU-6/B AIM-120A Air-to-Air 6, Transferred to ABL. B-1 Escape Capsule Rocket Motor Note Separation/ejection Not used on B-1. HARM Rocket Motor AGM-88 Air-to-Ground 10, HARM AUR Missile Assembly M15 JATO AGM-88 Air-to-Ground 14, Aircraft auxiliary thrust; sled track 150, s Co-producer with Thiokol. M34 ZEL booster Aircraft boost Zero-launch for F-100. Megaboom RS-B-101 Sled propulsion Mk 25 JATO Aircraft auxiliary thrust 11, Mk 36 Mod 2 (Smoky AIM-9C/D Air-to-Air 4,600 Early RDS-500) 1960s Mk 36 Mod 6/7/8 Sidewinder (Smoky) AIM-9L Air-to-Air 6, Mk 36 Mod 9/11 Sidewinder (Red. Smoke) AIM-9L/M Air-to-Air 15, Mk 38 Sparrow AIM-7E Air-to-Air 24, Post 1995 production at ABL. Mk 39 Shrike AGM-45A Air-to-Ground 15, Very similar to Mk 38. Mk 47 Phoenix AIM-54A Air-to-Air 5, Mk 50 Chaparral (Smoky) MIM-72A Surface-to-Air 819 Nearly identical to Mk 36 Mod 5. Mk 70 Mod 0 Condor AGM-53A Air-to-Ground Program cancelled 1976 Mk 112 RAM RIM-116 Surface-to-Air 1, Post 1995 production at ABL. 15

16 Motor Roadrunner booster (subsonic) Roadrunner booster (supersonic) Missile System ID No. Use Dates Note Made MQM-42 Auxiliary boost MQM-42 Auxiliary boost Saturn H-1 Gas Generator Engine starter 1960s Saturn S-II Ullage Motor Stage acceleration Sea Lance EX-116 UUM/RUM- 125A Anti-ship Sled JATO RS-B-402 Sled propulsion Tartar/Terrier APU Auxiliary power 20, s- 60s Teal XKDT-1 RS-D-101 Drone booster Thor DM-18 Retro Separation/ejection 1960s- 70s Trident I C4 Third Stage Eject Motor UGM-96A Separation/ejection 1970s Trident II D5 Third Stage Eject Motor UGM-133A Separation/ejection s Turbine Starter Gas Generator Gas generator 8,000 Variable Flow Ducted Rocket (VFDR) Gas generator (gg) & booster (b) 54 (gg) & 6 (b) Program cancelled (gg) static & 26 engine direct-connect tests; transferred to ABL VIII. Prologue At the time ATK vacated the facility, NWIRP McGregor consisted of approximately 9,770 acres of land. Of this, about 8,000 non-industrial acres were subsequently leased for agricultural uses that included cattle grazing and production of grain crops. Following a series of Government studies, environmental remediation activity, and Congressional action, the plant property was turned over to the City of McGregor in a series of conveyances for the purpose of economic development. Areas E and D were the last to be transferred to the city. Today, only vestiges of the town s rich solid propulsion manufacturing heritage remain. The site of the former plant is now known as the McGregor Industrial Park (Fig. 27). Several small businesses have leased former plant manufacturing and storage areas, while other buildings sit vacant among overgrown prairie vegetation (Fig. 28). Many World War II-era bunkers in Area H remain (Fig. 29), but no longer store bombs or rockets. The Rocket Federal Credit Union in town still serves former plant employees who reside in the area. Ironically, a small portion of the McGregor Industrial Park continues to support the U.S. rocket industry, occasionally supplanting the quiet central Texas prairie with the sounds of large liquid rocket engine testing. In 1998, the short-lived and privately funded Beal Aerospace Company of Frisco, Texas, first leased the 120-acre Area L from the City of McGregor for the testing of liquid engines for its BA-2 heavy lift launch vehicle. Beal made major modifications to an existing horizontal thrust stand (Building 1140B), shown in Fig. 30, and began construction of a 240-ft vertical test stand nearby. From five to 40 employees worked at the McGregor test site on any given day. Beal s work culminated with the successful 21 second test of its 810,000-lbf vacuum thrust BA-810 kerosene/hydrogen peroxide engine on 4 March However, citing lack of Government support for private launch vehicle development, Beal ceased operations in October From 2003 until the time of this writing, another privately funded startup company, Space Exploration Technologies (SpaceX) of El Segundo, California, leased the Area L site for the testing of liquid engines for its Falcon launch vehicles. SpaceX completed the construction of the vertical test stand and associated infrastructure (Fig. 31), using it to conduct test firings of its Merlin engine beginning in 2007 (Fig. 32). 16

17 After sitting vacant for nearly 10 years, Dell Incorporated and the City of McGregor entered into a lease agreement to refurbish and upgrade the former A-100 for the purpose of establishing a Dell call center there in May A December 2000 photograph (Fig. 33) shows the vacant former A-100, while a 2005 photograph (Fig. 34) shows the reoccupied facility which employed approximately 250 people. Dell abruptly closed and vacated the call center in October 2007, and Cincinnati-based Convergys took over the lease in Figure 27. Sign for McGregor Industrial Park. Figure 28. Building A-106 built in Figure 29. Storage Bunkers in Former Area H. Figure 30. Test Stand 1140B in Area L. Figure 31. SpaceX s Big Falcon Test Stand (BFTS) in Area L. Figure 32. Multi-engine Merlin firing at McGregor. Credit: SpaceX 17

18 Figure 33. Former A-100 in December Figure 34. Reoccupied former A-100 in May Credit: City of McGregor Acknowledgments The authors gratefully acknowledge former McGregor employees William H. Miller and Thomas R. Kirk for their contributions to this paper. Glossary AMRAAM ATK CNC CTPB DoD HARM HTPB NASA TIG = Advanced Medium Range Air-to-Air Missile = stock ticker symbol for Alliant Techsystems Incorporated = computer numeric control = carboxyl-terminated polybutadiene = Department of Defense (United States) = High-speed Anti-Radiation Missile = hydroxyl-terminated polybutadiene = National Aeronautics and Space Administration (United States) = tungsten inert gas References 1 Moore, Dick, Texas Revisited Rocketdyne at McGregor Relives North American War Time Operation in the Lone Star State, Skyline (a publication of North American Aviation Inc.), Vol. 17 No. 4, Fall 1959, pp. 36, Corrie, Walter S. Jr.., Sentinel of Victory: A Brief History of the Bluebonnet Ordnance Plant, a term paper for History 204, Spring Quarter 1947, in The Texas Collection, Baylor University, Waco, Texas. 3 Design of a Pilot and Manufacturing Control Plant for Composite Propellant Rocket Development, Report RF, Contract AF 33(600)-22913, Phillips Petroleum Company, McGregor, Texas, 28 August Development of Composite Propellant JATO Units, Final Report RF, Contract AF 33(600)-6710, Supplements 6, 10, and 15, Phillips Petroleum Company, McGregor, Texas, 15 August 1956, p Solid Propellant Progress, Jet Propulsion (Journal of the American Rocket Society), Vol. 26 No. 6, June 1956, p A Chemical Engineering Survey of the Solid Rocket Propellant Industry in the United States, Rohm & Haas Company, Huntsville, Alabama, September 1957, p Moore, T. L., U.S. Rocket Motor Designation Guide, Chemical Propulsion Information Agency, February Solid Propellants A Survey, Solid Propellant Information Agency (SPIA), Silver Spring, Maryland, July 1956, pp Moore, Dick, Fastest Gas in the West, Skyline (a publication of North American Aviation Inc.), Vol. 19 No. 2, April-June

19 10 Dimon, Richard B., Solid Citizen Rocketdyne s Plant in McGregor Texas is Introducing a New Generation of Air-Launched Missile Rocket Motors, Skyline (a publication of North American Aviation Inc.), Vol. 23 No. 2, April-June 1965, p Tormey, J. F., Butarez CTL-I Polymers and Propellants Their Reproducibility and Aging Characteristics, ICRPG Propellant Binder Symposium, CPIA Publication No. 139, February 1967, pp Dimon, Richard B., Solid Citizen Rocketdyne s Plant in McGregor Texas is Introducing a New Generation of Air-Launched Missile Rocket Motors, Skyline (a publication of North American Aviation Inc.), Vol. 23 No. 2, April-June 1965, pp Environmental Assessment: Disposal or Retention of the Naval Weapons Industrial Reserve Plant (NWIRP), McGregor, Texas, Department of the Navy, November 1998, p Dimon, Richard B., Solid Citizen Rocketdyne s Plant in McGregor Texas is Introducing a New Generation of Air-Launched Missile Rocket Motors, Skyline (a publication of North American Aviation Inc.), Vol. 23 No. 2, April-June 1965, p Moore, T. L., Polybutadienes Dominate for 40 Years, CPIA Bulletin, Chemical Propulsion Information Agency, Vol. 24, No. 2, March 1998, pp Caveny, L. H., Geisler, R. L., Ellis, R. A., and Moore, T. L., Solid Rocket Enabling Technologies and Milestones in the United States, Journal of Propulsion and Power, Vol. 19, No. 6, November-December 2003, p Davenas, A., Development of Modern Solid Propellants, Journal of Propulsion and Power, Vol. 19, No. 6, November-December 2003, p PHOENIX to Make Final Propulsion Delivery, TEX-SUN (a publication of Hercules Incorporated, McGregor, Texas), Vol. 15 No. 13, July 15, 1992, pp Wilson, R., Limage, C., and Hewitt, P., The Evolution of Ramjet Missile Propulsion in the U.S. and Where We are Headed, Paper AIAA , 32 nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Lake Buena Vista, Florida, July 1996, p McClendon, S. E., Miller, W. H., and Herty III, C. H., Fuel Selection Criteria for Ducted Rocket Application, Paper AIAA , 16 th AIAA/SAE/ASME Joint Propulsion Conference, Hartford, Connecticut, June-July Miller, W. H., McClendon, S. E., and Burkes, W., Design Approaches for Variable Flow Ducted Rockets, Paper AIAA , 17 th AIAA/SAE/ASME Joint Propulsion Conference, Colorado Springs, Colorado, July Wilson, R., Limage, C., and Hewitt, P., The Evolution of Ramjet Missile Propulsion in the U.S. and Where We are Headed, Paper AIAA , 32 nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Lake Buena Vista, Florida, July 1996, pp.5-6 and Hewitt, P. W., Worldwide Developments in Ramjet Powered Missiles, JANNAF 26th Airbreathing Propulsion Subcommittee Meeting, Destin, Florida, April 2002, CPIA Publication 713, Vol. I, pp Moore, T. L., Solid Rocket Development at Allegany Ballistics Laboratory, Paper AIAA , 35 th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Los Angeles, California, June