Nov 17, 2016

RF Resonant Cavity Thruster (EmDrive) - Is it Impossible still?

The human is confined to the earth. The blue marble is his natural habitat, away from which, he has no destiny. Separation from consumable energy sources and close contact with strange atmosphere make the earthly life forms incapable of survival in space.

But the human is genetically adventurous. So they attempted space travel. The ancient and intrinsic humane curiosity about the celestial bodies gave way for his hunt to find similar planets that can sustain life forms. The adventure that started as a quick visit to the upper orbit levels eventually led him to land on earth’s natural satellite, the Moon. And now, he is on the lookout of possible other worlds where he can survive in an earth-like atmosphere before the earth becomes inhabitable anymore.

The Blue Marble, Earth's famous photograph taken by the crew of Apollo 17.
Courtesy: NASA
Leave that story aside. Let’s now think about the historical evolution of human’s travel modes. The man who wandered completely unclothed around the forests reached an evolutionary landmark when he invented the wheel.  He ultimately learned to travel via the land, the water and the air using vehicles. The history says us that there were certain inventions which acted as the milestones of the growth of the human transport. The invention of the steam engine might be one such. The recently developed Hyperloop technology may be another one, which is another story. When humans developed rocket propulsion technology, it helped him to travel out of earth’s protective environment.

If the man is continuing his space expeditions, the existing rocket-propelled methods would become unreliable very soon, due to the cost involved. Factors to be considered here include the amount of fuel required for the initial launch from the earth and the cost for refuelling in case the plan is for an interplanetary travel (interstellar may be in the far future). Spacecraft once used is totally or partially unusable for a second expedition, which is another important factor in this regard. I am not ignoring the fact that we are planning a manned launch to the Mars with the existing rocket-propelled methods, but for how long we can rely on such costly methods? If an intelligent alien species is furtively watching our space expeditions, we are being constantly pooh-poohed by them for still depending on such age-old methods. I don’t believe in intelligent extra-terrestrials (aliens) by the way; my points regarding this are another topic, about which I might write later.

At this point, we have the concept of EmDrive or RF Resonant Cavity Thruster. The Emdrive (pronounced M-drive) is a device for transportation which requires no propellants. It is currently being built using a hypothetical method of converting microwave energy into thrust inside a closed chamber. Imagine a spacecraft that goes up effortlessly without any blast or cloud of smoke, and goes beyond the pull of earth’s attraction in a comparatively shorter span of time! That marvellous achievement will be the result of Em Drive’s successful construction. If you have seen movies about aliens, you might have noticed that in many cases the vehicles used by them are launched without any apparent thrust.

The man behind Em-Drive is Roger Shawyer. You can see here a video in which he explains his concept. I am just an amateur Physics enthusiast, sadly not an expert to understand fully what he details in the video.

Full interview: Roger Shawyer, Creator of EmDrive

There were many predecessors of EmDrive, one of them was called Cannae Drive (formerly Q-drive), and there were also some other claimed anti-gravity drives. Some of such devices are either under development or were stopped when found futile. Roger Shawyer’s Em Drive is operated by a thrust, which is the result of the reaction between the end plates of the waveguide used in it, and the electromagnetic wave propagated within it (and thus the name, Em Drive, which may be called Electromagnetic Drive).

EmDrive's Sample Flight Thruster. Courtesy:
Now, the sad part! The scientific world is mostly against this concept. They think this device will not work as it violates Newton’s Third Law, (which deals with the reaction that follows every action), and the theory of Conservation of Momentum. But, somehow, NASA takes Roger Shawyer seriously and they now seem to follow every development of EmDrive, though in a sceptic manner. A recent article which appeared in SPACE website also says this device might work, which is a lot of encouragement for the space enthusiasts. You may read the article in the below link:

The EmDrive may or may not work. But as a layman, I feel that it is high time that a revolution in space travel took place. As I had heard in somewhere before, the best shape that a spacecraft is to be built is that of a circular disc, as it is the best shape to skip through different atmospheres of varying gravity and pressure. (That’s why the UFOs always had a disc or circular shape?) If not EmDrive, probably a different device might soon be invented that would make the human species a spacefaring one, let us hope.

(Disclaimer: This is not a scientific article. The opinions in the article are the author's own.)


  1. All this reminds me of the Professor in Spielberg's "Back to the Future"

    1. I will watch that film. Sadly I haven't watched. Thanks for the suggestion.


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