Startup Makes Progress in Beamed Propulsion for Reusable Launch Vehicles

 

SAN JOSE, Calif. — A small Colorado company has successfully tested a new type of propulsion technology that it believes could eventually enable low-cost, single-stage-to-orbit launch vehicles.

Broomfield, Colorado-based Escape Dynamics announced July 17 it carried out a small-scale test in the laboratory of its beamed microwave thruster. In that test, the company beamed microwave energy to a thruster, heating helium propellant and generating a small amount of thrust.

"Using microwave-powered propulsion is really what we think is the next giant leap in space access," said company president Laetitia Garriott de Cayeux during a presentation at the NewSpace 2015 conference here July 17. [Superfast Spacecraft Propulsion Concepts (Images)]

 

Unlike conventional chemical propulsion, where the energy is stored in the propellants themselves, beamed microwave propulsion stores the energy on the ground and transmits it to the launch vehicle using microwaves. A heat exchanger on the launch vehicle converts the microwaves into thermal energy to heat up a propellant, such as hydrogen and helium, which is then expelled to generate thrust.

That concept reduces the complexity of the launch vehicle. "It's essentially a tank, a turbopump, a heat exchanger, and an aerospike nozzle," Garriott said. "It's overall very simple compared to a chemical rocket."

The beamed microwave propulsion technology is also more efficient than chemical propulsion. The most energetic propellants in common use today, liquid oxygen and liquid hydrogen, have a specific impulse — a measure of rocket engine efficiency — of about 450 seconds. Garriott said the beamed energy thruster tested in her company's lab had a specific impulse of more than 500 seconds, and could achieve up to 750 seconds by using hydrogen instead of helium