NASA tests methane engine components for future landers

A thruster, the combination of an injector and chamber, roared to life in a series of tests recently at Marshall’s Test Stand 115. The distinct blue flame is produced by the thruster’s fuel, methane. Photo Credit: NASA Marshall Space Flight Center

Engineers at NASA’s Marshall Space Flight Center recently tested components for a methane-fueled engine that could be used on future Mars landers. Methane is a promising potential fuel for the journey to Mars because it is more stable than hydrogen and can be stored at more manageable temperatures. It may also be possible to recover or create methane from local resources on Mars, using in-situ resource utilization (ISRU). “With the current configuration, these methane thrusters could propel a small lander,” said Steve Hanna, lead for NASA’s Advanced Exploration Systems at Marshall. “With the data gained from these tests, the technology is scalable for even larger applications for in-space engines and larger landers.”

Because methane has a storage temperature that is similar to liquid oxygen that will serve as an oxidizer for methane-fueled engines, methane storage tanks will require less insulation, leading to more affordable tanks. The tanks can also be smaller because methane is denser than liquid hydrogen, today’s most common rocket fuel.

On the upcoming Mars 2020 mission, NASA plans to demonstrate ISRU technologies that could enable the production of propellant and breathable oxygen from the Martian atmosphere. These technologies could allow astronauts to create both the fuel and oxidizer needed to propel an ascent vehicle into Mars orbit.

The 3-D printed, methane-powered thruster consists of an injector, left, and chamber, right. The 3-D printing techniques allow Marshall engineers to incorporate thermocouple ports into the chamber’s design, which collect discrete data during testing. Photo Credit: NASA Marshall Space Flight Center

The current thruster being tested at Marshall is part of a pressure-fed design capable of producing 4,000 pounds-force (17.8 kN) of thrust. Engineers at the center are also developing a pump-fed design capable of producing the 25,000 pounds-force (111.2 kN) of thrust need for larger ascent and descent landers on Mars. In the larger engine design, a turbopump with a turbine capable of up to 95,000 revolutions per minute will deliver fuel to the thruster, providing higher thrust levels. The turbopump will also allow the engines to be throttled as needed.

The engineers at Marshall have recently conducted successful preliminary testing and facility checkout of a turbopump for a methane engine. A series of tests are planned for later this year to verify that the turbopump, which had been previously tested using liquid hydrogen, can also be used with methane and deliver enough fuel for a large methane engine.

Both the thruster and the turbopump were manufactured using additive manufacturing, also known as 3-D printing. 3-D printing allows for quicker production times and a reduction in the machining and brazing required using traditional manufacturing methods. The technique also allows for the addition of thermocouple ports along the length of the thruster’s chamber. These ports communicate with the chambers coolant channels, providing precise temperature data that was never available before.

“This data will help critical thermal modeling,” said Sandra Greene, an engineer in Marshall’s Propulsion Systems Department. “That’s why the thermocouple ports are so exciting – we not only get the inlet and exit temperature of the methane, but we also get data to help us verify what is happening inside the chamber’s coolant system.”

Video courtesy of NASA.

Tagged: Lead Stories Marshall Space Flight Center NASA

Jim Sharkey

Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.