Colorado space startup Escape Dynamics announced today that they've successfully tested a prototype of their spaceship engine and are ready to move on to their next phase in development. By itself, that doesn't sound like huge news - companies all over the world are testing prototype engines for rockets.
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.
In an industry where "game changer" is thrown around with aplomb, this could be the real thing. Rockets powered by beams of power from the ground, enabling them to be more efficient and carry greater payloads.
"The key is moving beyond chemical rockets," Escape Dynamics President and COO Laetitia Garriott de Cayeux told me. "It’s been the same technology for over 50 years – chemical propulsion to escape Earth’s gravity. But there are two key limitations with chemical propulsion: The cost makes it prohibitive, and also, there’s a complete lack of routine, on-demand launch capabilities."
Escape Dynamics' vision for spaceflight is much different. 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.
While that sounds complicated (and it is), the benefits for launching spaceships is enormous. The energy comes from the grid and/or renewable power, rather than more expensive rocket fuels. It's also more efficient.
The efficiency of rockets are generally measured by their specific impulse, which is the ratio of how much thrust a rocket produces to the weight flow of its fuel. Traditional chemical rockets have a specific impulse of 460s, which is why they rely on multiple stages to reach orbit - one rocket engine firing isn't enough.
That need for multiple stages is part of what drives the cost of rockets (and in turn, why companies like SpaceX are trying to make that first stage reusable in order to drive those costs down.) But with external propulsion, Escape Dynamics believes that it can reach specific impulses greater than 600s - great enough that it only needs a single stage to make it to orbit.
That's what made their in-lab test of their engine so promising. Those tests showed that their engine reached a specific impulse of over 500s. And those tests, for safety reasons, used helium rather than hydrogen as a rocket propellant. Had hydrogen been used, the company's CEO and CTO Dmitriy Tseliakhovich told me, their computer modeling indicates the impulse would have been over 600s.
The next step for the company will be to test their system in the open air in the desert, beaming power over hundreds of meters at an engine that uses hydrogen as a propellant. Once successful, those tests will be followed by flying drones via microwave beaming.
If that's successful, then the third major testing phase will be building a large-scale system capable of sending a spaceship into space (but not orbit), followed by their final plan of building full scale infrastructure (including a square kilometer of antennae) to power a ship into orbit and bring the craft back down.
None of it is going to be cheap. Garriott told me that the R&D phases up to suborbital flight are expected to cost about $200 million, and the total cost to scale up to full orbital flights will be around a billion dollars. Which means the capital for the next phases of their development will need to be raised as the company moves along its development path.
The company's current primary investor and Chairman of its Board, Richard F. Schaden, isn't worried about raising it, though, and expects to have a capital raise in a few months.
"We have interested investors now!" he told me. "So far it's been our choice not to use it. The capital we need for the next phases is fairly readily available. I've gotta make some decisions."
If all goes as planned, the company expects to have its flights going in the early 2020s. But it anticipates that the capability for efficient, low-cost, high-frequency launches will be of enormous value.
"It’s a long term project, but ultimately it’ll be very profitable," said Schaden. "It will substantially reduce the cost of putting satellites in low Earth orbit."
Tseliakhovich added, "Affordable, reliable space access will change how we live. The amount of things that can be done is mindblowing. I hope we get there as soon as possible."
