Related by context. Frequent words. (Click for all words.) 73 propulsion 68 electric propulsion 56 hybrid electric 54 hybrid propulsion 52 PEM fuel 51 turbine engines 51 TARDEC 51 tactical wheeled 51 electro optic 50 electric powertrains 49 aerospace 49 rocket propulsion 48 hypersonic 48 subsystems 48 powertrains 48 electrically driven 48 unmanned 47 proton exchange 47 avionics 47 hybrid powertrains 47 unmanned aerial 47 astronautics 47 & Whitney Rocketdyne 47 Propulsion 46 NYSE ORB 46 diesel engines 46 planetary missions 46 motors 46 NYSE GY 45 Orbital Sciences Corporation 45 aeronautics 45 Li ion batteries 45 measurement instrumentation 45 drivetrains 45 composite materials 45 powertrain 45 Smart NanoBattery 45 rocket motors 45 actuators 45 turbomachinery 45 payloads 44 internal combustion engines 44 nanostructured materials 44 Based Infrared 44 robotics 44 technologies 44 electric powertrain 44 aero engine 44 combustor 44 combustion engines 43 C4ISR 43 autonomous underwater 43 hydrogen fuel 43 Aegis Weapon System 43 electric drivetrain 43 planetary exploration 43 Orion spacecraft 43 hydrogen 43 unmanned aerial vehicles 43 manned spacecraft 43 airships 43 SOFC 43 electromagnetics 43 SOFCs 43 undersea warfare 43 hydrogen powered 43 thruster 42 jet propulsion 42 lithium polymer batteries 42 flywheels 42 electric motors 42 AESA radar 42 spacecraft 42 mechatronic 42 unmanned underwater 42 Launch Vehicle 42 diesel engine 42 AUVs 42 subassemblies 42 payload 42 P 8A 42 gaseous hydrogen 42 vacuum furnace 42 rotorcraft 42 NYSE ATK 42 electromechanical 42 X #A 42 hydrodynamics 42 solid propellant 42 aero engines 42 vertical takeoff 42 Airbus A# XWB 42 Tank Automotive 42 X #B 42 Lithium ion 42 Crew Exploration 41 gearboxes 41 Orion capsule 41 Dragon spacecraft 41 powertrain components 41 diesel powered