Testing Future Engine Technology is a Work of Art

An engine nozzle turns a dramatic array of colors during a recent hot-fire test at NASA's White Sands Test Facility near Las Cruces, N.M. A team of engineers from Glenn Research Center in Cleveland, Ohio, Marshall Space Flight Center in Huntsville, Ala., and Johnson Space Center in Houston conducted tests on a cryogenic liquid oxygen and liquid methane engine to measure the engine's performance for future use with in-space vehicles.

Testing of the Aerojet Liquid Oxygen/Liquid Methane Ascent Main Engine Technology Workhorse Engine. Credit: NASA/WSTF
Last month, eight altitude chamber tests were performed using an Aerojet workhorse engine to gather design data for future lander and in-space engines. Using the altitude chamber, which simulates the space-type vacuum environment, engineers were able to attach a larger nozzle and vary the propellant mixture ratios to test the engine's overall operating capability. This technology could be selected for future use with vehicles designed for transport, descent, or ascent to another planetary body or asteroid.

The nozzle, or large bell-shaped hardware, directs the flow of the combustion products from the liquid methane fuel and liquid oxygen oxidizer mixture and accelerates the exhaust gasses to generate thrust. The nozzle material is made of columbium and heats up during the test causing the color change. The nozzle is radiatively cooled and once the engine shuts down, the nozzle returns to its previous color.

Another test objective was to look at the specific impulse, or gas mileage, this engine could provide to a space vehicle. Specific impulse is simply a measurement of the amount of thrust that can be attained per mass of rocket propellant consumed. The higher specific impulse attained improves the overall rocket performance and reduces the weight of propellants that need to be carried on the vehicle.

Overall, the test series was successful and valuable performance data was obtained. Data received from the tests is currently being reviewed to ensure the engine performed as expected on a continual basis with each individual test.

Engineers will continue to vary and refine the engine test parameters to evaluate the technology further. Developing technology is a test-rich process to ensure as many unknowns are worked out on the ground before this technology is put into application in a space environment.

The cryogenic liquid oxygen and liquid methane effort is part of the Propulsion and Cryogenics Advanced Development (PCAD) project at Glenn, which is developing cryogenic propulsion technologies for future space exploration missions. The PCAD project is funded by the Exploration Technology Development Program in NASA's Exploration Systems Mission Directorate.

Contact: Kim Newton
Marshall Space Flight Center, Huntsville, Ala.