You want to believe that a prototype propulsion engine has been built which generates thrust by bouncing microwaves around inside an enclosed metal funnel which produces no mass or energy outside the engine and violates one of the tenets of physics – the conservation of momentum.
About 15 years ago, British inventor Roger Shawyer unveiled what he called the EmDrive, a prototype engine which he said exploited a sort of loophole within general relativity and would lead to what hopeful people – most of them ‘science writers’ – immediately called “warp drive.”
There is, however, this thing called the scientific method which requires actual, observable, repeatable results aside from headlines like “EmDrive is an Engine That Breaks the Laws of Physics and Could Take Us to Mars.”
Considering for a moment that a propellant-less thruster capable of moving a spacecraft with nothing more than microwaves would be a monumentally wonderful thing, the fact that the idea just won’t go away is easy to explain.
Is it the next Alcubierre Drive? Who knows? Indeed, who knows what an Alcubierre Drive actually is other than some NASA theorists?
What we do know is that propulsion in space as it is now understood relies on Newton’s laws of motion. In those systems, propellant is ejected backward at velocity, and a spacecraft is thereby pushed forward with this whole equal and opposite momentum thing.
Shawyer says his EmDrive does not produce any exhaust as we know it, and it’s essentially a conical or megaphone-shaped construction which channels resonating microwaves. Shawyer says a “pressure” exerted inside the large end of that cavity is greater than the pressure at the smaller end, and he says that condition produces a net thrust.
So making one is the subject of no little interest, so Paul Kocyla, a professional hardware developer, coder and space enthusiast, has used 3D printing to take on the task of studying the effect.
“The EMDrive is basically a closed microwave waveguide with a changed geometry, so one of the ends is bigger,” he writes on Hackaday. “When RF is fed into the cavity and a resonance is achieved – according to Shawyer a thrust force will occur.”
The megaphone-shaped cavity in Kocyla’s example was 3D printed in silver, which he says is “a very suitable material for waveguides due to its conductivity.” The cavity was created in polished silver by Shapeways, and then isolated in a set of 3D printed plastic mounts.
Do you believe an engine like the EMDrive will change the course of history and spacecraft design? Let us know in the 3D Printed EMDrive forum thread on 3DPB.com.