A Multiple Launch Rocket System (MLRS) rocket motor is installed in J-6 Large Rocket Motor Test Facility before test firing. Paint stripes on the top of the MLRS rocket motor, is temperature-indicating paint that monitors temperature range between 200 to 1,200 degrees Fahrenheit. (Photo by Rick Goodfriend)
AEDC outside machinist J. R. Dunham prepares a Minuteman Stage III motor before testing in J-6 in 2003. Operators fired the randomly selected motor at a simulated altitude of 100,000 feet to qualify the motor’s production lot. The test confirmed contaminants in the propellant did not impact motor performance.
Tom Farmer, an Aerospace Testing Alliance (ATA) outside machinist, makes final verification checks of the ORBUS rocket motor before the test firing at the center’s J-6 Large Rocket Motor Test facility. ATA is the support contractor for the center.
The J-6 facility provides ground test simulations for solid-propellant rocket motors over a wide range of simulated pressure altitudes.
These tests support materials and structural development efforts by the Department of Defense and commercial aerospace industry.
AEDC has unique test capabilities for testing rocket propulsion systems with high performance/high area-ratio nozzles, and those requiring altitude start and restart, stage separation and spin testing.
These facilities are the largest of their kind in the world and provide the only altitude test capability for medium to large and rocket propulsion systems in the United States.
The base engine test facility exhaust plant, combined with the unique close coupled annular steam ejector, provides optimal control of pressure transients that occur during engine ignition and shutdown. This unique configuration provides an optimum test capability to safely test rocket propulsion systems utilizing fragile, high performance (high area-ratio) nozzles.
Connection to the exhaust plant also allows for extended run times at simulated altitude conditions required for many propulsion systems used in orbital transfer operations.
Ambient (sea level) testing of rocket propulsion systems designed for high altitude operations can compromise engine performance data and potentially jeopardize the structural integrity of the nozzle by imposing severe loads from nozzle flow separation. Sea-level testing with truncated nozzles does not properly evaluate nozzle structural integrity. It also requires the test data to be adjusted to calculate full-nozzle and thrust vector control systems performance.
Ground testing under simulated altitude conditions in J-6 include carefully-controlled test environments with extensive instrumentation and photographic coverage to determine the operability and performance of a test article.
Testing can include an extensive array of sophisticated rocket diagnostic instruments obtainable only in a ground test configuration. State-of-the-art techniques such as wide-band infrared and ultraviolet radiometric coverage, emission/absorption detection, laser-induced fluorescence plume surveys, and real-time radiography are some of the applications frequently used.
A combined simulated-altitude ground test and flight test approach can greatly mitigate program risk, reduced test program cost and provide greater understanding of true system performance.
J-6 is designed to test large detonable solid-propellant rocket motors with up to 80,000 pounds. Measuring 26 feet in diameter by 62 feet long, the horizontally oriented test cell is capable of testing rocket motors at simulated pressure altitudes up to 100,000 feet. The temperature-conditioning system can maintain the test cell at an air temperature within the range of 15 to 110 degrees Fahrenheit (± 5F) from motor installation until pre-fire pump down at altitude conditions.
J-6 supports long-duration altitude tests, of high-area-ratio nozzle performance including deployment operation with dynamic loads and thermal stresses ignition performance tests, stage separation testing, heat transfer and posttest heat soaking tests and failure analysis (propellant extinguished). The facility can be used to test many different types of motors with either large quantities or advanced mixes of propellants.
The facility is equipped with three interchangeable rocket diffusers and can accommodate thrust ranges from 5,000 to 500,000 pounds force. The test cell is connected to a 250-feet diameter by 100-feet-high concrete dehumidification chamber that can also be used as a vacuum chamber to support special tests associated with space vehicles and rocket plume studies.
J-6 fulfills a national need for testing large solid-propellant rocket motors at simulated altitudes. The J-6 design makes it ideal for use with many state-of-the-art diagnostic tools including acoustic sensing, real-time radiography, laser positioning systems, infrared and ultraviolet imaging and high-speed video. The test cell digital data acquisition system is designed to acquire up to 500,000 samples per second.
Since becoming operational in 1994, J-6 has been used for aging surveillance, change verification and qualification testing of Stages II and III for both Minuteman and Peacekeeper weapon systems. Additionally, J-6 supports STAR 37 motor qualification testing for the Air Force's Global Positioning Satellite (GPS) constellation.
A complete range of test support services are available at AEDC in connection with the Rocket Test Facilities. Support services include model design, fabrication, and assembly, test article instrumentation, instrument calibration, and data analysis. Test articles can be provided ready to test by the test user, or fabricated and instrumented at AEDC to user specifications.
Benefits of Altitude Testing
-- No risk to flight vehivle
-- Lower cost
-- More instrumentation
-- Close observation
-- Recoverable case/engine nozzle
-- Realistic ignition
-- Accurate impulse
-- Better fidelity for durability
Key Performance Objectives
1. High area-ratio nozzle behavior
2. System thrust and impulse
3. Heat transfer characteristics of both engine and vehicle base regions