Electric Hypersonic Spaceplane

As of 2026, no one has ever reached orbit without using rocket propulsion for the majority of the mission. Yet hundreds of alternative launch methods have been proposed. Everything from railguns to cannons to elevators has been studied. The Tsiolkovsky rocket equation is clear on the subject—you really do not want to bring your own reaction mass. The penalty is enormous. Yet nothing that has ever reached orbit has done so on a launcher with less than 88% propellant mass.

Air-breathing engines have been studied extensively. Generally, as velocities increase, complexity increases as well: propellers, jets, ramjets, scramjets, and finally the SABRE engine. However, none have taken an electrification approach.

Here, I propose a novel type of hypersonic engine using modulated magnetoplasmadynamic thrusters, with reaction mass and energy recovery from an air-turbine inlet. The engineering challenges are extreme. There is nearly a gigawatt of recirculated energy, requiring efficiencies of nearly 98%. But with formidable challenges come formidable rewards. A launch vehicle of this class could not only use less than 10% propellant mass, but could also reach orbit with more reaction mass than it took off with—an advantage for subsequent in-space propulsion.

More coming soon.