Escape Dynamics is developing the first single-stage-to-orbit, reusable launch vehicle powered with external propulsion. In external propulsion energy required for launch is delivered from a ground-based phased array of microwave antennas designed to safely and efficiently beam flight-sustaining power to the space plane during the ascent and acceleration to orbital velocity. The energy is converted into thrust in a heat exchanger which absorbs microwaves into heat and couples the energy into the flow of hydrogen propellant. The heated hydrogen is exhausted through the nozzle creating thrust and accelerating the vehicle.

Externally powered engines designed by Escape Dynamics operate with specific impulse above 750s and propellant mass fraction below 72% (compared to almost 90% of chemical rockets) and for the first time enable reusable single-stage-to-orbit flight.