The biggest obstacle in the quest to put manned missions into deep space has always been the time it takes to get there. With the current types of propulsion systems, it would take about nine months to get a spacecraft, crew and enough supplies for the trip, all the way to Mars. The technology exists to get there, however keeping a crew fed, healthy and sane on the way is the key problem.
Solutions include inducing human stasis, having crewmembers rotate sleep and wake cycles and of course finding a propulsion system that can cut the travel time down. Using something else besides costly rocket fuel would be an advantage as well. Recently there has been a lot of talk about an EM drive, a power source that uses electromagnetic waves inside a closed engine to produce power. NASA is developing one at the Johnson Space Center and seeing some promising results.
There is also a team at Dresden University of Technology in Germany that has tested their version of an EM drive, or as it's known a "resonant cavity thruster." Lead scientist for the project, Martin Tajmar, a professor and chair for Space Systems at the Dresden University of Technology, and his colleague G. Fiedler were in Orlando, Florida this week at the American Institute for Aeronautics and Astronautics' Propulsion and Energy Forum where their findings were the subject of much discussion.
Tajmar and his team reported that their model actually produced thrust similar to prior tests on other models, including the Eagleworks engine, built by NASA. Tamjar's study claims that his model was tested in the exact same conditions, but in his study, he was able to better eliminate errors and other interferences in the prior projects.
But lets back up and take a look at how the concept works. First, electric power is used to generate microwaves inside the closed framework of the thruster. The microwaves then bounce around and the energy produced from that reaction creates thrust that can, in theory, propel a spacecraft. Estimates are that a spacecraft powered by an EM drive engine could make the trip to Mars in just 70 days. The project is not without it's detractors however.
There is no exit point for the energy created to leave the thruster. In conventional rockets, the fuel heats up, produces thrust and then the propellant exits the engine so it can cool down and this after-burn balances the thrust. This is in line with Newton's Third Law of Conservation of Momentum. With the EM drive, there is no expelling of energy or burned fuel, so it violates this law and technically should not work.
In an interview with io9, a Senior Research Physicist at the Institute for Advanced Studies at Austin, Eric W. Davis refutes the results of the German team saying that the thrust measured is likely a result of the device getting hot while operating. In talking about Tamjar's concluding paragraphs Davis said, "He also stated that he was still recording thrust signals even after the electrical power was turned off which is a huge key clue that his thrust measurements are all systematic artifact false positive thrust signals."
While headlines around the world are saying that the "impossible" engine has been proven to work, the reality is that the findings of the German team remain preliminary and have yet to be peer-reviewed. What is not in question is that this theory is as revolutionary as the move from sail to steam was for ships and it demands a closer look from all sides.
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