Except Escape Dynamics didn’t fire its engine by setting alight fuel in a controlled explosion, like a traditional rocket. Instead, their engine fired using power beamed at it from a microwave antenna across the room.
]…] It aims to use a giant set of batteries to draw power from the regular electric grid (or on site solar panels, wind turbines, or other available power generation). Once they’re charged and a spaceship is ready to go, power will be sent to a set of modular, phased array microwave antennae spanning a square kilometer. Those antennae will then fire a microwave beam at a heat exchanger on the spaceship. That heat exchanger will heat up the hydrogen in the fuel tank, which is what powers the rocket on the ship into orbit.