Since vibrations conducted through the air create sound, we also study the acoustics associated with engines and propulsion systems. Space Propulsion NASA Glenn was a pioneer in research of rocket engines with liquid hydrogen and liquid oxygen as propellants. Today, NASA Glenn remains a major contributor to this technology area. Reusable engines must be more durable and designed to be maintainable without a loss in performance. NASA Glenn research also includes on-board propulsion systems for attitude control, station keeping, and other functions.
Rocket engines vary in size and functionality depending upon the mission.