Don’t buy stock yet in that “impossible” space drive

The uncertainty of science and engineering: A physicist takes a close and skeptical look at the “impossible” space drive that NASA engineers discovered seemed to work. Key quote:

“All in all,” Lee concluded, “it will take a lot more information before we can judge whether the thrust is really a thrust or not.”

Read the whole article. They point out the areas of doubt and weakness, as well as the possibilities.

NASA confirms “impossible” drive

Life imitates science fiction: NASA engineers have confirmed the functionality of an “impossible” space thruster drive.

British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems, but critics reject his relativity-based theory and insist that, according to the law of conservation of momentum, it cannot work.

According to good scientific practice, an independent third party needed to replicate Shawyer’s results. As reported, this happened last year when a Chinese team built its own EmDrive and confirmed that it produced 720 mN (about 72 grams) of thrust, enough for a practical satellite thruster. Such a thruster could be powered by solar electricity, eliminating the need for the supply of propellant that occupies up to half the launch mass of many satellites. The Chinese work attracted little attention; it seems that nobody in the West believed in it.

However, a US scientist, Guido Fetta, has built his own propellant-less microwave thruster, and managed to persuade Nasa to test it out. The test results were presented on July 30 at the 50th Joint Propulsion Conference in Cleveland, Ohio. Astonishingly enough, they are positive.

Since no one understands the physics that are producing the thrust, it is wise at this point to be very skeptical of these results. A lot more testing and experimentation will be necessary before this can be made practical.

However, if it is what they think it is, it will make it possible to turn sunlight into thrust, meaning that spacecraft will no longer need fuel, and will be able to go places much faster using the constant thrust this drive will provide.