For every action there is a reaction: that is the principle under which all space rockets operate, throwing propellant in one direction to travel in the opposite. But now a NASA engineer believes he could take us to the stars without the need for any propellant. He wants to create an engine powered by a particle accelerator.
Called «helical motor», the concept is to accelerate ions confined in a closed circuit with the mass increasing when moving forward and decreasing when it bounces back, thus producing the thrust effect that, according to its creator, will be able to reach the 99 percent of the speed of light without breaking Einstein’s theory of relativity.
And although the idea of an engine powered by a particle accelerator has been received with skepticism, that has not discouraged those who thought: «I am comfortable with presenting this idea. If it doesn’t work, I’ll be the first to admit it, but it’s worth a try, ”said its creator David Burns, of the Marshall Space Flight Center in Alabama.
To give us an idea of the principle on which the engine powered by a particle accelerator suggested by Burns works, imagine a box on a frictionless surface. Inside that box is a bar around which a hoop slides. Spring gives the ring an initial impulse to go to the side. When the ring reaches the wall of the box, it bounces in the other direction, and the bounce direction of the box also changes. This is action-reaction – also known as Newton’s third law of motion – and, in normal circumstances, restricts the box to wiggle back and forth:
But Burns wonders, what if the mass of the ring were much larger when it moved in one direction than in the other? Then he would give the box a greater “kick” on one side than the other. This action would exceed the reaction and the box would accelerate forward:
This change of mass is not something prohibitive for physics. Einstein’s theory of special relativity says that an object gains mass as it is driven towards the speed of light, an effect that can be observed in a particle accelerator. In fact, a simplistic implementation of the concept would be to replace the ring with a circular particle accelerator, in which ions are rapidly accelerated at relativistic speeds in one direction and decreased in the other.
But Burns thinks it would make more sense to extend the simple box and the bar in the same way to the sides, in a circular motion that would give it a helix look.
It would also be necessary for the engine to be huge – 200 meters long and 12 in diameter – and powerful, requiring 165 megawatts to generate just one newton of momentum – which is the same force you use to type on the keyboard. For that reason, the engine would only be able to achieve significant speeds in a frictionless environment such as that of outer space. “The engine itself would be able to reach 99 percent of the speed of light with enough time and power,” Burns explains.
A known concept
This type of concept without propellants is not new. In the late 1970s, American inventor Robert Cook patented an engine that supposedly turned centrifugal force into linear motion. Then, at the beginning of this century, British inventor Roger Shawyer proposed the EM Drive (also an RF resonant cavity propeller), which he proclaims is capable of converting trapped microwaves into propulsion. Neither of these concepts has been successfully demonstrated and both – until now – are considered by the scientific community as impossible to implement, especially given the violation of the conservation of linear momentum, a fundamental principle of physics.
Em Drive: The engine uses a magnetron to produce microwaves that are directed to a metal, conical, fully enclosed vessel capable of isolating radiation by functioning as a resonant cavity. This vessel would have the shape of a truncated cone on two sides, a larger face where the thrust would be produced and a smaller face where a dielectric resonator would be found. The apparatus would require a source of electrical energy to produce the microwaves that are reflected inside but do not have any moving parts or require any propellant.
Martin Tajmar of the Dresden University of Technology in Germany, who was involved in recent tests of the EM Drive engine, believes that the helical motor would likely present similar problems. “Every inertial propulsion system – as far as I know – has never worked in a friction-free environment. This machine makes use of special relativity, unlike others, which complicates the picture, ”he says. “Unfortunately there will always be action-reaction.”
Source: New Scientist