Each action corresponds to an equal and opposite reaction: third law of dynamics. It is the principle on which space rockets are based, which burn propellant in one direction to go in the opposite direction.
However, a NASA engineer believes he can take us to the stars without any propellant, thanks to a special helical motor. An engine that would be the basis of all the spaceships of the future.
Drawn by David Burns of the Marshall Space Flight Center in Alabama, the “helical engine” exploits the effects of mass alteration that occur at speeds close to the speed of light. Burns published a paper describing the concept on NASA's technical reports server.
Needless to say, his work has met with skepticism from some of his colleagues, but Burns believes the concept is valid, and will pave the way for many space engines of the future. “If someone proves it doesn't work I won't have any problem changing my mind, but it's worth exploring this option too,” he says.
How does the helical motor work?
To understand a little the principle of the helical-shaped engine created by Burns, try to imagine a box on a surface that has no friction. Inside the box there is a bar around which a ring slides. If an impulse inside the box pushes the ring, it will slide forward while the box goes in the opposite direction. Once it hits the edge of the box, the ring will move back, and the box will too, reversing its direction. Under normal conditions the third law of dynamics produces an oscillation from right to left of the ring.
But what would happen, Burns asks, if the mass of the ring was larger when it went in one direction and then smaller when it came back in the opposite direction? In fact the action would be greater than the reaction, the third law of dynamics would be bypassed and the box would move further and further forward.
How can that ring change its mass?
This is not “forbidden” by physics. Einstein's special theory of relativity says that an object gains mass as it approaches the speed of light (an effect that can be demonstrated to a small extent by current particle accelerators).
In fact, if we replace the ring in the box with a particle accelerator we have obtained the result. The ions inside the ring would be driven to speeds close to that of light (increasing mass) when going in one direction and decelerating (decreasing mass) when going in the other.
It can be done even better
Burns thinks that the system would be even more efficient if the stick and ring were dispensed with, and everything was replaced with a single helix-shaped particle accelerator, capable of making the particles perform both lateral and longitudinal movements: a helical movement, precisely.
What about the box?
At a guess, a rather large one would be needed. It is no coincidence that the dimensions of this engine are in the order of 200 meters in length and 12 in diameter. The energy required is also enormous, according to calculations: 165 megawatts of energy are needed to generate the thrust equal to 1 newton (it is the force we use to press a key on the keyboard).
For this reason the engine can only work in a "big frictionless box" (or almost): cosmic space.
“With the right amount of time and energy, this engine could reach 99% the speed of light in space,” Burns says.
An electromagnetic motor with thrusters, but without propellant
At the end of the 70s, Robert Cook, an American inventor, patented the design of an engine capable of converting centrifugal force into linear movement.
30 years later, in the early 2000s, the English inventor Roger Shawyer proposed the EM drive, which he said was capable of converting microwaves into thrust.
In January 2017, a magnetic motor developed in NASA's Eagleworks Laboratory seemed to have hit the target, but more detailed tests revealed a design error in these magnetic propulsion engines. Phenomenon also known as "how to melt an engine".
Neither concept has yet been successfully tested: both are judged impossible for their violation of a key physics law, the law of conservation of angular momentum.
Martin Tajmar from the Dresden University of Technology in Germany has tested (unsuccessfully) the EM Drive and believes the helical motor will likely have the same problems.
“The way I see it, no inertial propulsion system will ever work in space environments,” he says.
The principle of this impossible engine respects special relativity, which makes it special, but “unfortunately there is always an action-reaction mechanism to consider”.
Burns has worked on his own, and admits that the engine model is rather inefficient. However, it is without prejudice to the principle, and believes that there is potential for improvement.
“I know the risks associated with presenting technologies such as cold fusion or EM Drive,” He says. “I know my reputation will be discussed, but you have to take the risk if you want to invent something new”.
The impression is that of being faced with very interesting ideas from an extremely embryonic project. All the ideas are present, but the whole seems premature.
