Mythical space, the engine finally will be the real test

Since the birth of the space age dream of a trip to another solar system was kept in a “missile Bay”, which severely restricts the speed and size of the spacecraft we launch into space. Scientists estimate that even using the most powerful rocket engines today will take about 50,000 years to reach our nearest interstellar neighbor, alpha Centauri. If people ever hope to see the sunrise of an alien sun, the transit time must be dramatically reduced.

Does the impossible EmDrive engine?

Among the advanced concepts of the engine, which could move all this off the ground, very few have caused as much excitement — and controversy — as EmDrive. First described almost twenty years ago, the EmDrive works by converting electricity to microwaves and the direction of electromagnetic radiation through a tapered chamber. Theoretically, microwaves can exert pressure on the chamber wall and to create sufficient traction for the movement of a spacecraft in space. At the moment, however, EmDrive only exists as a laboratory prototype, and it is still unclear whether he is able to do to create traction. If and creates, the force that is strong enough to be seen with the naked eye, not to mention the fact to move the camera.

However, over the past few years, several scientists, including NASA, claimed to have successfully produced thrust from EmDrive. If this is true, we are waiting for one of the biggest breakthroughs in the history of space exploration. The problem is that the thrust observed in these experiments, so small that it is difficult to say whether it exists at all.

The solution is to develop a tool that can measure these slight manifestations of traction. Therefore, a team of physicists from the German Technische Universität Dresden decided to create a device that would solve this problem. The project SpaceDrive, led by physicist Martin taymarom, is to create a tool so sensitive and immune to interference that he once and for all put an end to the discussion. In October Taymar and his team submitted its second set of experimental measurements of the EmDrive at the International Astronautical Congress, and their results will be published in Acta Astronautica this August. Starting from the results of the experiments, Taymar said that the resolution of the Saga with EmDrive is waiting for us in a few months.

Many scientists and engineers do not believe in the EmDrive since it violates the laws of physics. Microwave, pushing the walls of the chamber EmDrive apparently, generate traction ex nihilo, i.e. from nothing, which goes against the conservation of momentum — action and no resistance. The proponents of the EmDrive in turn, looking for answers in clever interpretations of quantum mechanics, trying to understand how could work EmDrive without violating Newtonian physics. “From a theoretical point of view, no one takes it seriously,” says Taymar. If EmDrive capable of generating thrust, as claimed by some groups, “no one has any idea where it comes from.” When in science there is a theoretical gap of this magnitude, Taymar sees only one way to close it: experimental.

At the end of 2016 Taymar and 25 other physicists gathered in Estes Park, Colorado, at the first conference on EmDrive and related exotic propulsion systems. One of the most interesting speeches were made by Paul Marsh, a physicist of NASA Eagleworks laboratory in which he and his colleague Harold white tested various prototype EmDrive. According to the presentation of the March and the subsequent report, published in the Journal of Propulsion and Power, he and white have observed a few tens of micronewtons thrust in our prototype EmDrive. For comparison, a single SpaceX Merlin engine produces approximately 845 000 Newtons of thrust at sea level. However, the problem for the March and white was the fact that their experimental setup included several sources of interference, so they couldn’t say for sure what was due to traction, or a specific obstacle.

Taymar and the Dresden group used an exact copy of the prototype EmDrive, used in the laboratory NASA. It is a copper truncated cone with the top cut off — with a length slightly less than a foot. This design invented by engineer Roger Scheuer, who first described the EmDrive in 2001. During the test, the cone EmDrive is placed in a vacuum chamber. Outside the camera device generates the microwave signal which is transmitted over coaxial cables to the antenna inside the cone.

This is not the first case when the team in Dresden is trying to measure nearly imperceptible force. They created a similar device to work on ion engines, which are used to accurately position satellites in space. These micronewtons engines help satellites to detect weak phenomena, such as gravitational waves. But EmDrive and similar engines without fuel will need nanonewton resolution.

The new approach was to apply torsion scales, pendulum balance, which measures the amount of torque applied to the axis of the pendulum. Less sensitive version of this balance was also used by the NASA team when they decided that the EmDrive produces thrust. To accurately measure this small force, the Dresden team used a laser interferometer to measure the physical displacement of the balance weights produced by the EmDrive. According to Tamara, their torsion scales have nanonewton resolution and support of the steering device weighing several kilograms that makes these pull weights are most sensitive available.

But truly sensitive pull weights are unlikely to be useful if you cannot determine whether the detected force is a thrust, not a manifestation of outside interference. And there are manyexplanations for the observations of March and white. To determine whether the EmDrive produces thrust in fact, scientists should be able to shield the device from interference of the Earth’s magnetic fields, seismic vibration environment and thermal expansion EmDrive associated with heating by microwaves.

According to Tamara, changes in the design of the torsion balance, to better control the power source EmDrive and protect it from magnetic fields will allow to solve a number of interference problems. Where it was more difficult to solve the problem of “thermal drift”. When power is supplied to the EmDrive, copper cone heats up and expands, which shifts its center of gravity so that the torsion balance registers the force, which mistakenly can be taken for traction. Taiman and his team hoped that the change in the orientation of the engine will help to solve this problem.

In the course of the experiments 55 Taymar and his colleagues recorded the average 3.4 micronewton forces from EmDrive, which was very similar to that found in NASA. Alas, these forces have apparently not had the test on the thermal offset. They were more characteristic of thermal expansion than the thrust.

But for EmDrive hope is not lost. Taymar and his colleagues are also developing two additional types of weights of traction, including superconducting balance, which will help to eliminate false alarms caused by thermal drift. If they find strength from EmDrive on these scales, there is a high probability that this is really a boost. But if no thrust scales will not reveal, it would mean that all previous observations EmDrive thrust was a false positive. Taymar hopes to get a final verdict before the end of the year.

But even negative results will not mean a sentence to EmDrive. There are many other types of engines without fuel. And if scientists ever develop a new form of motion on low-powered, ultra-sensitive traction weights will help to separate fiction from fact.