NARTS collage header

NARTS Test Area D and E

NARTS Historic District Sign

A separate Navy installation stood adjacent to the north and east of Picatinny Arsenal until 1960. This was the Lake Denmark Powder Depot (famous for the 1926 explosion), later named the Naval Ammunition Depot, which became obsolete after World War II. The installation received a new lease on life, however, in the late 1940s, when its well-protected lands were turned into rocket-engine testing facilities. These were developed partly by a local, private firm, Reaction Motors, Inc. (RMI), and partly by the Navy for its in-house rocket research program. Reaction Motors, seeking a secluded site in the Denville area, first leased land and buildings here from the Navy in mid-1946. They built 9 rocket test stands and related facilities on the north side of Snake Hill Road, and continued work on their 6000 series engines, including the 6000C4 (later called the XLR-11), which would power the Bell X-1 aircraft that broke the sound barrier in 1947. The Navy's Bureau of Aeronautics, which wanted a rocket-engine test center on the east coast, established the Naval Aeronautical Rocket Laboratory (NARL) at Lake Denmark in 1948. The advantages of this location included the installation's existing infrastructure; excellent transportation connections; relative proximity to Washington, D.C.; and access to specialized personnel and materials procurement in this highly-industrialized region of the country. The Navy's relationship with its tenant, Reaction Motors, was also an important factor – the company had already achieved a permanent place in the annals of flight, and NARL mechanics were initially trained by Reaction Motors staff for work at the facility. NARL built 11 more test stands and related facilities, infrastructure, and interim labs. The name was changed to the Naval Air Rocket Test Station – NARTS – in 1950, and expansion continued. Test Areas D and E belong to this period. Test Area D was completed in 1951, and Test Area E, adjacent but isolated on its own hilltop, was completed in 1953, boasting the Navy's premier rocket-engine testing facility at the time. Test Area D was used primarily for the Navy's in-house evaluation and development of rocket engines and propellants by the renowned team at the NARTS Rocket Propulsion Laboratory. Test Area E was usually used by NARTS tenant Reaction Motors, Inc. This is where RMI tested the XLR-99, the engine that would power the X-15. (RMI also continued to use and expand the facilities north of Snake Hill Road, called Test Areas A, B, C, and G, as well as Test Areas R and S, on property that the company owned further up Lake Denmark Road). In 1960-62, the Navy base was disestablished and its land and facilities were fully transferred to the Army's Picatinny Arsenal. The Rocket Propulsion Laboratory (with staff) became the Army's Liquid Propulsion Laboratory, and the test facilities were leased to the Thiokol Corporation, which was now Reaction Motors' parent company. Testing at the NARTS Test Area D and E Historic District would end in the early 1970s. In their two and a half decades of operation, these facilities played a significant role in the development of liquid rocket propulsion, supersonic flight, and the space program. See NARL 1950, NARTS ca. 1959

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NARTS Overview Map

(click on the image for a separate close-up view)

A geateway to space plaque

Commemorative plaque at Picatinny

Diagram for Liquid Rocket Engine

The main focus of NARTS was liquid propulsion

Test Areas

The Rocket Test Areas built between 1946 and 1953 can be seen on this circa-1960 aerial photograph. The view is to the south.

NARTS labeled aerial photograph

Role of NARTS

  • During the early years of the Cold War, the Navy vied with the other military services to lead rocket and missile development. Moreover, within the Navy two separate bureaus – the Bureau of Ordnance and the Bureau of Aeronautics – competed with each other for control of that service's expanding rocket and guided missile programs (the two would be merged into the Bureau of Naval Weapons in 1959). Meanwhile the government was increasingly shifting R&D for propellants and rocket motors to private industry. The "adoption" of Reaction Motors and establishment of NARTS by the Bureau of Aeronautics can be understood within this competitive context. But there was, in fact, a critical need: NARTS was created so that the Navy would have a central facility for testing the products of both contractors and in-house programs in a rapidly-evolving field.

  • The work of NARTS included evaluation of rocket engines and propellant systems, development of methods for analyzing rocket propellants, collaboration with private industry on experiments, and development of safety protocols. But through its tenant, Reaction Motors, the Lake Denmark facility also gave birth to the engines for the nation's most significant rocket and missile programs. Engines worked on here powered the LARK surface-to-air missile, the Bell X-1, the Douglas SKYROCKET, and the Martin VIKING. After Test Area E was built, it would be the Reaction Motors XLR-99 (the engine for the X-15) that would become the facility's chief claim to fame. Meanwhile, throughout the 1950s, the NARTS Rocket Propulsion Laboratory conducted its own rocket tests for the Navy as well as important basic research on propellants. See Lassman 2008, Panamerican 2007.

Click here to open a pdf file of an article on NARTS that appeared in the April 1951 issue of Naval Aviation News, a publication of the Navy's Bureau of Operations and Bureau of Aeronautics (now declassified). [pdf file size: 1.0mb]


LARK (NASM exhibit)




VIKING National Air and Space Museum (NASM 75-10228), Smithsonian Institution.

WPA Workers repairing railroad tracks

Work in 1951 included everything from chemistry

WPA workers laying steam lines

to machining

WPA work construction of building 115

to electronics

Liquid Propulsion

  • James H. Wyld

    James H. Wyld in 1941 with his regeneratively cooled motor.  Princeton University Libraries.

  • Although Robert H. Goddard launched the first successful liquid propellant rocket in 1926, the heyday of liquid propulsion research was from the late 1940s to the early 1960s. It was in this field that both Reaction Motors and NARTS were significant players. In a liquid rocket, the fuel and the oxidizer (which together make up the "propellants") are stored separately as liquids, then pumped into a combustion chamber where they burn when combined. Combustion produces exhaust gas, which is passed through a nozzle to accelerate the flow and produce thrust. It is possible to adjust or stop the thrust during flight by turning off the flow of propellants (unlike with solid propellants, which burn up completely once ignited). Liquid rockets are relatively complex and heavy, requiring storage tanks and either pumps or pressurization, and the propellants need to be loaded into the rocket just before launch. Liquid-fuel engines need to be cooled for stability, especially for long-duration and manned flights. One of the founders of Reaction Motors, Inc., James H. Wyld, developed a regeneratively-cooled rocket motor in 1938-41, which led to the company's success in furnishing motors for early research aircraft. Experimentation with various oxidizer/fuel combinations (such as liquid oxygen with gasoline, ammonia, or ethyl alcohol), on monopropellants (which did not need an oxidizer), and on a multitude of fuel additives, was the focus of much of the research undertaken in the post-war period. The Rocket Propulsion Laboratory at NARTS was an important center for testing and basic research on propellants and propellant handling.

    Reaction Motors included an explanation and diagrams of engine types in its 1953 company prospectus.

  • Types of engines diagram

    Reaction Motors, 1953, page 3

A Rocket Scientist

  • Dr. John D. Clark

    Dr. John D. Clark was Chief Chemist at NARTS and its successor, the Liquid Rocket Propulsion Laboratory of Picatinny Arsenal, from 1949 until his retirement in 1970. Clark was a hard scientist – he received his PhD from Stanford in 1934 and worked in private industry before coming to Lake Denmark – but he also had a long-standing interest in science fiction and fantasy. In the 1930s and early 40s he published two science fiction short stories of his own, "Minus Planet" and "Space Blister," was influential in the popularization of the Conan stories, and counted among his friends many writers, including Fletcher Pratt and Isaac Asimov. Spider In 1944, purportedly because Clark's friends disliked his new wife and wanted a way to get together on their own, they formed a semi-secret men's club in New York, made up mainly of science fiction writers, called the Trap Door Spiders. The club was later fictionalized by Asimov in a mystery series as the "Black Widowers," with Clark as the character named James Drake.

  • Ignition book cover

    Clark was clearly a "character" in real life too – one whose adventures as a bona fide rocket scientist began once he joined the staff of the Navy's new laboratory at Lake Denmark. Under his direction, the NARTS Rocket Propulsion Laboratory's Propellant Division undertook basic research on new propellants and performed tests as needed for government contractors (including NARTS's tenant, Reaction Motors). Among other projects, Clark and his staff conducted research on new high-energy liquid monopropellants, which could withstand impact and be heated to more than 300°F without exploding. Clark published a book, Ignition! An Informal History of Liquid Rocket Propellants, in 1972 (Rutgers University Press, forward by Isaac Asimov), recounting in a highly engaging way the general development of this very technical field as well as some "fiery" incidents at his lab and others. See NY Times, July 9, 1988; Clark 1972; Martin Gardner Interview Part 4 2008, Trap-Door Spiders,

Reaction Motors

  • Reaction Motors logo

    Reaction Motors, Inc. (RMI) was founded in 1941, just as the US entered World War II, by four members of the American Rocket Society: James H. Wyld, Lovell Lawrence, Jr., John Shesta, and Hugh Franklin Pierce. Their business aim was to further development of the regeneratively-cooled liquid propellant engine that had been devised a few years earlier by Wyld, and to sell the idea of using rockets with these engines to the military – specifically the Navy's Bureau of Aeronautics, which gave the company its first contract following the attack on Pearl Harbor. During the war, RMI developed Jet-assisted take-off (Jato) engines for Navy sea planes, utilizing the regeneratively-cooled principle that the company had helped pioneer, but it was rockets that most interested these men.

    RMI's first home was in an 800-square-foot garage, containing an office and a machine shop, in Pompton Plains, NJ. They did their testing out the back door, or at their earlier test site at Franklin Lakes. By 1943 the company had expanded, moving to a 3-story building (originally a silver factory and later a night club) in the same town that had 3 and a half acres of land on which to build test stands. Local complaints about the noise and perceived danger from testing engines led to lawsuits and denials of permits, forcing RMI to seek a new location. In 1946 the Bureau of Aeronautics (BuAer) stepped in, and RMI moved its testing to the then-obsolete Navy Ammunition Depot at Lake Denmark. (BuAer created their own rocket test station at Lake Denmark soon afterward, with RMI's experienced technicians on hand to train Navy staff.) RMI moved their administrative and manufacturing functions to a facility in Rockaway in 1949, and in 1955 opened a new plant in Denville. Testing continued to be conducted at Lake Denmark, where facilities were expanded and modernized through the mid-1950s.

  • Pierce, Shesta and Lovell

    Pierce, Shesta, and Lovell conduct a test in 1942. National Air and Space Museum, Smithsonian Institution (SI 82-4616).

Navy training

Reaction Motors Navy training at Lake Denmark

Navy trainingr
Navy training
  • In the early years, RMI's costs for developing rocket engines far exceeded the fixed-price contracts that they received, and the company was in serious debt by the time they came to Lake Denmark. Rescue came in the form of an investment by Laurence S. Rockefeller in 1947. With fresh capital, RMI was able to expand. By 1951there were 642 employees, and sales numbers had improved dramatically, reaching $4.5 million. But business was just "taking off." Mathieson Chemical Corporation, soon to merge into Olin Mathieson, bought a controlling interest in the firm in 1953, and by 1958, Reaction Motors had 1,639 employees and over $24 million in sales. In that year, while working feverishly under contract to build the XLR-99 engine, they merged with the Thiokol Chemical Corporation and became that firm's Reaction Motors Division. The relatively rapid subsequent demise of Reaction Motors came with increasing competition in the field and the Navy's turn away from liquid-fueled rocket research in the 1960s. The division was gradually phased out and ceased to exist in 1972.

    In addition to the rocket engines that secured its place in the history of aviation and space exploration, Reaction Motors worked on many less-famous projects for the military, such as a steam catapult for aircraft carriers, helicopter rotors, fireproofing for NASA, and the Bullpup guided missile. The company also created a corporate culture that led to enduring camaraderie among its alumnae. Forty years after Reaction Motors was closed down, its proud employees gather for semi-annual reunions. And while members of the founding generation have passed on, the accomplishments of this small northern New Jersey company continue to be recognized both locally and nationally. See Ordway and Winter 1983, Winter and Ordway 1985; Winter 1994a, 1994b.

"Black Betsy"

Diagram of 6000 engine

The Reaction Motors 6000C-4 engine, from Rocket Encyclopedia Illustrated, 1959

6000 engine

Engine in the collection of the National Museum of the US Air Force

  • "Black Betsy" was the nickname for Reaction Motors' 6000C-4 rocket engine, which powered the Bell X-1 aircraft famously flown by Captain Charles E. "Chuck" Yeager to break the sound barrier on October 14, 1947. The engine would later be re-named the XLR-11. This "power plant" (as rocket engines were called) burned an oxidizer/fuel combination of liquid oxygen and ethyl alcohol and utilized the regenerative cooling design developed by James Hart Wyld. "6000" refers to pounds of thrust: 1500 per cylinder in the four-cylinder engine.

    The motor was developed beginning in 1945, starting out as a Navy Bureau of Aeronautics project and then being transferred to the Army Air Force (predecessor of the Air Force), which had teamed up with Bell Aircraft Corporation to create a "transonic" aircraft. The Reaction Motors 6000C-4 engines were installed on the first two Bell XS-1 (subsequently called X-1) aircraft in 1946 and 1947. Early test flights out of Muroc Army Base (now Edwards Air Force Base) were successful, and the planes were turned over to the National Advisory Committee for Aeronautics (NACA) and the Army Air Force for supersonic tests in June of 1947. The aircraft made a combined total of 135 test flights through 1950. Milestones in addition to Chuck Yeager breaking the sound barrier include: reaching a top speed of Mach 1.45 in March 1948; taking off from the ground under its own power in January 1949 (previously the aircraft were always air launched from a Boeing B-29); and reaching its maximum altitude of 71,902 feet in August 1949. These first 6000C-4 engines used a pressurized fuel feed system, requiring heavy tanks of gaseous nitrogen. But from the beginning in 1945, Reaction Motors had been developing its lighter but more complex turbo pump version of the engine, using hydrogen peroxide to pressurize the pumps. Variants of this design would power the later X-1A, B, C, D and E aircraft of the 1950s. Yeager flew the X-1D to Mach 2.4 on December 12, 1953, the maximum speed for the aircraft, and Arthur Murray reached a top altitude of 90,440 feet in the X-1A on August 26, 1954.

  • Turbo pump 6000C-4 engines were also built for the Navy's Douglass Skyrocket D-559-2, though design differences were dictated by the aircraft specifications. For instance, while the engine for the Bell X-planes had the four cylinders arranged in a diamond pattern, the D-558-2 engine's cylinders were arranged in a square. The first Douglass Skyrocket with the rocket engine installed flew on February 25, 1949. Additional programs that used Reaction Motors 6000C-4 engines included the XF-91 experimental supersonic combat fighter, the MX-774 Intercontinental Ballistic Missile, and the first X-15. See Winter 1994a, 1994b.

Yeager with Glam Glenn

Chuck Yeager named the Bell X-1 that he flew to break the sound barrier the "Glamorous Glennis" after his wife. The plane was donated to the National Air and Space Museum in 1950. National Museum of the US Air Force.

Bell X-1

The Bell X-1 in flight. National Air and Space Museum, Smithsonian Institution (SI 97-17485).

Lawrence with engine

Lovell Lawrence with the engine. National Air and Space Museum (NASM 00166233), Smithsonian Institution.

Testing the 6000C-4 engine

Testing the 6000C-4 engine on the Large Rotary Beam Test Stand at Lake Denmark,
in Test Area C

Douglass Skyrocket

Douglass Skyrocket

The X-15

X-15 with twin 6000C-4 engines

This illustration from the Rocket Encyclopedia Illustrated, 1959, shows the first X-15 with twin Reaction Motors 6000C-4 engines

6000 engine

X-15 launch B-52 mothership, 1959. NASA Dryden Flight Research Center Photo Collection (NASA photo E-4942).

XLR-pp engine

X-15 with Reaction Motors XLR-99 engine. National Air and Space Museum, Smithsonian Institution (SI 83-16760).

  • Double 6000C engine

    National Air and Space Museum, Smithsonian Institution (SI 89-1868).

    In 1956, Reaction Motors was awarded the contract to build the engine for the X-15, a joint program of NACA/NASA, the Air Force, the Navy, and North American Aviation, Inc. Development of the new liquid-propulsion engine (called the XLR-99) was fraught with technical difficulties, missed deadlines, and cost overruns, and government oversight of the work at Lake Denmark became increasingly tight, with a technical advisory group formed in 1958. For their part, Reaction Motors (which became a division of Thiokol in that year) cited the safety and reliability requirements for a rocket engine intended for a "man-rated" (safe for a human pilot), throttle-able aircraft as reasons for technical problems and delays. The first X-15 test flight, which, as was typical, was an un-powered glide flight, was flown by Scott Crossfield at White Sands Proving Ground in June 1959. Crossfield piloted he first powered flight in September of that year – but the XLR-99 engine was still in development, so the early X-15 was powered by a pair of Reaction Motors 6000C-4 engines, the same motor that had been used on the Bell X-1. After 24 flights with the interim twin motors, the X-15 was fitted with the XLR-99 in 1960. Reaction Motors had delivered its second path-breaking rocket engine, the most famous product of the huge vertical test stand at NARTS Test Area E. It delivered 57,000 pounds of thrust, using liquid oxygen and anhydrous ammonia as propellants.

    The X-15's engine was the most successful manned throttle-able rocket in the world. In their total 199 flights, the three X-15 hypersonic aircraft set records for speed (in the Mach 4-6 range) and altitude (67 miles), reaching the "edge of space." The X-15 research program contributed to the development of the Mercury, Gemini, and Apollo space programs, as well as the Space Shuttle program, before the aircraft performed its last flight in October of 1968. See Garber 2000, Houston et al. 1998, NASA Fact Sheet 2009.

    NASA's Dryden Flight Research Center web site has an interactive feature on the X-15, which can be accessed from our Links page. []

Bell X-1

I Worked Here

Mario Luperi

Mario Luperi

Retired Reaction Motors engineer Mario Luperi talks about the  X-15 program and recalls a 1959 test flight by  pilot Scott Crossfield.

  • Crossfield with X15

    Scott Crossfield and the X-15. National Air and Space Museum (NASM 9A08280), Smithsonian Institution.

  • Neil Armstrong

To The Moon

  • Surveyor III

    The Surveyor III, photographed on the moon during the Apollo 12 mission. (NASA AS12-1-H-48-7100).

Vernier Engine

National Air and Space Museum, Smithsonian Institution (SI 84-100007).

  • Research aircraft powered by Reaction Motors engines, including the X-1 and the X-15, were crucial to the development of the space program, but the company was also directly involved in space exploration vehicles. Reaction Motors Division of Thiokol Chemical Corporation (RMD) built and tested the vernier thrusters for NASA's Surveyor program, which sent seven robotic vehicles to the moon in 1966-68. Five of them made successful soft landings, and remain on the lunar surface to this day. The purpose of the Surveyor program was to engineer soft landings, obtain images (with on-board cameras) of the lunar surface, and perform mechanical and chemical analyses of the soil in preparation for manned landings.

    Here again, it was Reaction Motors' expertise in liquid propulsion rocketry that was called upon. Surveyor vehicles were launched and aimed from Earth orbit using solid fuel rockets, slowed prior to landing using solid fuel retrorockets which were then jettisoned, then maneuvered the final 11 kilometers to just above the lunar surface with three small Reaction Motors vernier engines run on liquid propellants. The propellants were monomethyl hydrazine hydrate fuel and an oxidizer known as "MONO-10," fed using pressurized helium. No igniter was needed because the propellants were "hypergolic" (burning upon contact). The engines could be throttled to between 30 and 104 pounds of thrust. Testing at Picatinny (in the former NARTS test areas) included operation of the motors in simulation of the moon landings.

    See Hicks 1985 (p. 127) [on line at], Thiokol Reaction Motors Division (NASA Press Kit for Surveyor III) 1967.

    I Worked Here

    David Struthwolf

    David Struthwolf

    David Struthwolf recounts his career from Navy pilot to conducting simulated trips to the moon at Picatinny during testing of the Reaction Motors Vernier thrusters.  

    Vernier Engine

    A Reaction Motors Division vernier engine for the Surveyor (courtesy of David Struthwolf).