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Environmental Cleanup and Closure

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NASA Santa Susana Field Laboratory History


The Santa Susana Field Laboratory (SSFL) is located on approximately 2,850 acres in the Simi Hills in Ventura County, California. The Simi Hills are bordered on the east by the San Fernando Valley and to the north by Simi Valley. SSFL is divided into four administrative areas – Area I, Area II, Area III, and Area IV – and two "undeveloped areas." Areas I, III, and IV and the undeveloped areas are owned and operated by the Boeing Company. Area II, consisting of 409.5 acres, along with 41.7 acres in Area I, are owned by the U.S. Government and used by NASA. The U.S. Department of Energy (DOE) has long held a lease on land in Area IV. The links provide a summary of the 60 year history of ownership and operations of the portions of the site known today as Area II and the LOX Plant portion of Area I. These areas have been used primarily for rocket testing.


Three Native American groups occupied Ventura County in the areas surrounding the Simi Hills during late prehistory: the Chumash, the Tongva, and the Tataviam. All were seminomadic hunter-gatherers, while the Chumash and Tongva focused much of their subsistence activities on marine resources, supplementing that with resources available inland.

Burro Flats Painted Cave is a prehistoric archaeological site that is famous for its pictographs (rock art paintings) and petroglyphs (rock art that has been scored or incised into the rock surface). The site also includes evidence of habitation. The Chumash of the Simi Valley and Simi Hills and the Tongva of the San Fernando Valley may both have visited the Burro Flats Painted Cave area. There is speculation that the area may have been an interface between the two groups, and the rock art has been described as suggesting both cultures.

Burro Flats Painted Cave was first occupied from at least A.D. 1100 until ca. A.D. 1810 to 1820, although its occupation may extend back in time to as early as A.D. 900.


After World War II, North American Aviation (NAA) leased and later purchased land in the Simi Hills for rocket engine testing. NAA formed the aerospace company called Rocketdyne, which later merged with Rockwell International Corporation (referred to here as Rockwell. Both the Rockwell and Rocketdyne names were associated with SSFL. In 1954, NAA obtained an adjacent 838-acre area of undeveloped land from Henry Silvernale and Elizabeth Hall. (Property ownership records identify Henry Silvernale and Elizabeth Hall as the earliest recorded owners of the property.) This new parcel included the land that would become Area II, as well as the 41.7 acres in Area I that later would make up the LOX (Liquid Oxygen) plant. These portions subsequently were transferred to the U.S. government.

In December 1958, NAA deeded three parcels of the former Silvernale property to the U.S. Air Force (USAF). Parcels 1 and 2, consisting of 409.5 acres, became the site of USAF Plant 57, now Area II. Parcel 3 was used for USAF Plant 64, now the LOX plant. The Grant Deed also granted legal access for roads.

Since 1954, Area II has been operated by Boeing, Rockwell, and its predecessor, NAA, under USAF facility contracts. In 1973, the USAF Plant 57 (Area II) land was transferred to NASA and the USAF Plant 57 designation was no longer used.

In 1976, the U.S. General Services Administration (GSA) transferred the LOX plant (USAF Plant 64) from the USAF to NASA, but the Air Force retained possession of the structures. Under the terms of a facilities contract, Rockwell administered the LOX plant for NASA. The LOX plant was removed in the early 1970s with the exception of a small weigh station and concrete tank supports.


Between 1954 and 1957, NAA built the Alfa, Bravo, Coca, and Delta test stands in Area II, under contract with the USAF. The test stand activation summary summarizes the year of activation and initial program for each of the large test stands.

The Area II major rocket engine programs table lists the major rocket engine programs under which Rockwell tested engines in Area II and their approximate duration. The summary includes programs performed for the U.S. Department of Defense (DoD) and NASA. The liquid-fuel rocket engines used in these programs burned a variety of fuels. Kerosene-burning engines required trichloroethylene (TCE) flushing to remove the residual hydrocarbons that were combustible and potentially explosive when exposed to LOX.

  • Rocketdyne developed a level of cleanliness for engine parts, a “LOX clean standard”, used at SSFL. This practice included procedures and requirements for hot-fire testing and decontamination of engine or component assemblies, including the TCE flushing procedures.

The total amount of TCE used per engine test varied between 36 to 108 gallons at the four test areas, according to the engines being tested.

A TCE recycling system was implemented at SSFL in 1961. After being flushed through the engines, TCE was then captured in a catch pan and contained in a storage tank until it was removed off site for recycling. This flow chart describes the TCE flushing process.

Use of the Delta area ceased in the mid-1970s. Engine and component testing continued past 1983 in the Alfa, Bravo, and Coca areas. TCE use was discontinued in 1994 at the Alfa and Bravo areas. TCE use at Coca was discontinued when those test stands were deactivated in 1988.

LOX Plant Operations

The Liquid Oxygen (LOX) Plant was located in the NASA portion of Area I. LOX was produced using a cryogenic process that liquefies air and the oxygen is separated from the nitrogen. The LOX Plant buildings and tanks were removed in the early 1970s. Asbestos and soil were removed from a 54,000 square foot area off the hillside near the LOX Plant in the late 1980s. Several drums were also removed at this time. A former waste oil sump, clarifier, and leach pit were excavated and removed in 1993. Additional asbestos removals were conducted in 1990 and 2007. The LOX Plant concrete foundations were removed in 1996. The area was graded after the foundations and aboveground concrete supports were removed in 1996, and the site has been re-graded to conform to natural topography.

The truck scale was refurbished in 1992. The truck scale and affiliated controls building are the only remaining structures at the LOX Plant.

Test Stand/Major Rocket Engine Programs

The Navaho Program was awarded to NAA by the USAF in 1946 to study supersonic missiles. The Navaho was a surface-to-surface missile manufactured by NAA. Even though it never reached operational status before cancellation in 1957, Navaho research development contributed to the aeronautical research program. The heavy Navaho vehicle weighed 136,000 kilograms, capable of Mach-3 speeds, and used an improved V-2 engine, was boosted into the air by three liquid-propellant rocket engines of 135,000 pounds of thrust each. Variants of these engines were developed for Army's Redstone, Jupiter. Thor, and Atlas engines. A mixture of LOX and jet propulsion (JP) fuel, fed the Navaho G-38 engines. Navaho engines were tested only in Area II between 1956 and 1957 at the Alfa and Coca areas. Approximately 472 tests were performed for the Navaho G-38 engine.

Atlas Program

Although the Army had shown great initiative in ballistic missile development, the Air Force became the dominant military service in long-range, ballistic missiles. The Air Force had the responsibility for developing the Atlas and Titan intercontinental ballistic missiles (ICBM), the Thor intermediate range missile, and later, the Minuteman, an all-solid-propellant missile.

The Atlas had a range of about 10 000 kilometers and a payload capability of 700 kilograms. The Atlas was powered by two 667-kilonewton (150 000 lb thrust) first-stage engines plus a 267-kilonewton (60 000 lb) sustainer engine. At launch, all three engines operated and at the end of first-stage operation, the two large engines were jettisoned leaving the sustainer engine to continue to operate during the second phase. Propellants for all three engines came from common tanks which constituted the bulk of the structure. Since Atlas jettisoned only its first-stage engines, it was called a 1 1/2 stage vehicle.

NAA developed the Atlas propulsion system for use in the USAF’s Atlas Intercontinental Ballistic Missile Program. General Dynamics/Convair was the lead contractor in the Atlas program with responsibilities for airframe design, assembly, and testing of the missile system. Atlas engines used Rocket Propellant (RP)-1 for the fuel and LOX for the oxidizer as the propellant combination. Atlas engines and thrust chambers were tested at all four Area II test stand areas between 1955 and 1957, during the time NAA owned the property. Approximately 1,511 tests were performed for Atlas engines and thrust chambers.

NASA joined the USAF as a sponsor of the Atlas program in 1958. Both the USAF and NASA had SSFL facilities contracts and Atlas development production contracts with Rockwell from the 1960s through the 1980s. Test firings also were performed under both agencies during this time. More than 75 percent of the Atlas flights were performed for the USAF. More than 7,000 tests were performed for Atlas engines and thrust chambers between 1958 and 1983 at the Area II test stands. Testing of Atlas engines and thrust chambers continued at Alfa through 2000 and at Bravo until its closure in 2005.

Jupiter Program

The Jupiter rocket was designed and developed by the Army Ballistic Missile Agency (ABMA). ABMA launched the Jupiter-A at Cape Canaveral, Florida, on March 1, 1957. The Jupiter vehicle was a direct derivative of the Redstone. The ABMA continued Jupiter development into a successful intermediate ballistic missile, even though the Department of Defense directed its operational development to the Air Force. ABMA maintained a role in Jupiter RD, including high-altitude launches that added to ABMA's understanding of rocket vehicle operations in the near-Earth space environment. It was knowledge that paid handsome dividends later.

The Jupiter Program was established by the Department of the Army in 1956 as an outgrowth of the Department of Defense’s Intermediate Range Ballistic Missile (IRBM) Program. The propellant combination for the Jupiter engines used LOX as the oxidizer and kerosene as the fuel. Testing and production of the Jupiter engines occurred both at SSFL and at Rocketdyne’s Neosho, Missouri plant. Approximately 118 tests were performed for Jupiter engines at the Alfa and Delta test areas from 1957 through 1963.

Thor and RS-27 Program

During this program time, the Army continued testing its Redstones and Jupiters and a new short-range field missile called the Pershing. The Navy was busy developing its submarine-launched Polaris missile system. The Air Force pushed ahead with its Thor Intermediate Range Ballistic Missile (IRBM) and its Atlas, Titan and Minuteman ICBM programs. The Thor later became the booster stage for NASA's dependable Delta launch vehicle, which has placed more satellites into orbit than any other rocket in the nation's fold.

The Delta family of rockets have been built and launched since 1960. Its roots go back to the days immediately following the launch of Sputnik in 1957, when the Thor was modified into a booster for Earth-orbiting satellites.

NASA's first satellite launch attempt on board Delta was Echo I in May 1960. Although it was not successful, the launch of NASA's Echo IA satellite August 12, 1960, started Delta on its way to becoming "NASA's workhorse." Until the early 1980s the Delta increased in size and capability, serving as NASA's primary launch vehicle for boosting communications, weather, scientific and planetary exploration satellites into orbit.

The Thor Program was initiated in 1955 by the USAF as part of its Intermediate Range Ballistic Missile Program. Development of the RS 27 engine began in 1971 for the Delta Program. The RS-27 engine was a hybrid of the H-1 (not tested in Area II) rocket engine and the Thor MB-3 engine. The engines were fueled by LOX and kerosene. At least 2,262 tests were performed for the Thor and RS-27 Delta engines at the Alfa, Bravo, and Delta test stands between 1955 and 1991. Testing for RS-27 engines continued into 2006 at the Alfa test stands.

E-1 Program

The E-1 engine was planned for use on launch vehicles, such as Saturn rockets. The E-1 Program was initiated in 1956 by Rocketdyne as part of the USAF’s Rocket Engine Advancement Program. The experimental engine was a precursor to the F-1 engine. The E-1 was the result of an effort to produce a single thrust-chamber rocket engine capable of 300,000 pounds of thrust. Previously, this level of thrust was possible only with clusters of smaller engines. The engine was propelled by a mixture of LOX and RP fuel. NASA sponsored approximately 24 tests performed for the E-1 thrust chamber and mainstage in 1959. Approximately 146 tests sponsored by USAF were performed for the E-1 engines and thrust chambers between 1956 and 1960. These tests were conducted in the Bravo and Delta test areas.

X-1 Program

The first generation X-1 aircraft changed aviation history in numerous ways, and not simply because they were the first aircraft to fly faster than the speed of sound. Rather, they established the concept of the research aircraft, built solely for experimental purposes, and unhampered by any military or commercial requirements. Although subsequent X-planes were built for a wide range of purposes - technology or concept demonstrators, unmanned test missiles, and even as prototypes in all but name - the X-1s were built to go faster than an aircraft had ever flown before.

Capt. Charles E. "Chuck" Yeager was selected as the pilot for flights to Mach 1. He made his first glide flights on Aug. 6, 7, and 8, 1947. On Oct. 14, Yeager reached a speed of Mach 1.06 at 43,000 feet, becoming the first man to fly supersonic.

The X-1 Program for rocket powered research aircraft was established in 1956 by the USAF. The X-1 engine, similar to the Thor and other early engines, demonstrated innovations in its ignition system and the starting sequence system that were later applied to improved versions of both the Thor/Delta and the Atlas engines. The engine used LOX and RP-1 as propellants. Approximately 393 tests were performed for the X-1 engine at the Delta test stands between 1958 and 1961.

The X-4 was designed to test a semi-tailless wing configuration at transonic speeds. Many engineers believed in the 1940s that such design, without horizontal stabilizers, would avoid the interaction of shock waves between the wing and stabilizers. These were believed to be the source of the stability problems at transonic speeds up to Mach 0.9.

The X-4 engine was an experimental version of the Atlas sustainer engine and was tested only during 1960. During that year, approximately 12 tests were performed at the Delta test stands.

F-1 Program

The origins of the Saturn launch vehicle concept are rooted in the research conducted within the Army Ballistic Missile Agency in the late 1950's. A rocket engine of tremendous capabilities would be needed if man ever embarked on lunar journeys or sent probes into deep space. As a result, development started in the 1950's on the 1.5-million-pound-thrust F-1 engine even before a vehicle was designed for it. The F-1 would burn the familiar liquid oxygen and RP-1, and was based on an initial concept for a 360,000-pound-thrust E-1 engine that would burn liquid oxygen and RP-1.

For a brief while, NASA considered using the F-1 on a vehicle of tremendous size, the Nova, which would be capable of direct flights to the Moon. The Nova never materialized, but the F- 1 did and would eventually be used in the first stage of the vehicle that would launch men on their way to the Moon. Five F-1 engines would provide a total thrust of 7.5 million pounds in the Saturn V S-IC stage.

The F-1 Program was established in earnest at SSFL in 1959. The F-1 engines, the largest and most powerful produced in the United States, were placed as a cluster of five at the base of a Saturn V launch vehicle. The F-1 was a liquid propelled engine that used LOX and RP-1. The engine was too large to test at SSFL. Testing of F-1 components was performed at the Bravo test area between 1960 and 1970.

Unless otherwise indicated, all images are provided by NASA.

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