To the surprise of many, a radical new type of spacecraft propulsion system appears to actually work.
NASA recently tested an experimental microwave thruster for a radical new type of spacecraft propulsion system—and to the surprise of researchers, the "physics-defying," fuel-less space drive appears to actually work.
Fuel takes up an enormous amount of space and weighs down current spacecraft, so it would be a tremendous breakthrough to essentially eliminate the need for it, as the "EmDrive" promises to do.
The drive generates thrust by "bouncing microwaves around in closed container" without any need for propellant,according to Wired UK, which has been following the work of its inventor for several years.
That would be Roger Shawyer, a British scientist who in 2001 formed a company called SPR to promote his EmDrive, though to little avail in the face of critics who "reject[ed] his relativity-based theory and insist[ed] that, according to the law of conservation of momentum, it cannot work."
Until recently that is.
Chinese Academy of Sciences researchers built and tested an EmDrive a couple of years ago, reporting in November 2012 that they had achieved success with the experiment.
"At an input power of 2.5kW, their 2.45GHz EmDrive thruster provides 720mN of thrust," Shawyer's SPR site noted. Those numbers meant propulsion delivered by an EmDrive could be "enough for a practical satellite thruster," Wired noted.
Such a drive would still need a power input, but the thrusters "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 tech site said.
Now a second EmDrive-like thruster has been built by U.S. scientist Guido Fetta, who recently worked with a five-person NASA research team at the Johnson Space Center in Houston to test it. Like the Chinese effort, Fetta's "Cannae Drive" actually works "in spite of the law of conservation of momentum," Wired said.
"The torsion balance they used to test the thrust was sensitive enough to detect a thrust of less than ten micronewtons, but the drive actually produced 30 to 50 micronewtons—less than a thousandth of the Chinese results, but emphatically a positive result," according to the site, which reviewed a paper presented by the NASA team at last week's 50th Joint Propulsion Conference in Cleveland, Ohio.
For now, EmDrives and Cannae Drives are clearly still in the experimental stages. There's certainly a big question to be answered about how the Chinese researchers were supposedly able to create a practical thruster while Fetta's effort would need to be vastly improved to ever actually move a spacecraft around.
But for a space community looking at everything from solar sails to ion drives as a means to travel more efficiently between the planets—as well as for potential asteroid deflection missions —another innovative propulsion system is likely to get a long, studious look.
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