Posted on 08/07/2014 5:01:48 PM PDT by ETL 2
The roots of the propulsion system tested by the NASA team trace back to a British researcher named Roger Shawyer, who claims that his "EmDrive" generates thrust by rocketing microwaves around in a chamber. There is no need for propellant, as solar power can be used to produce the microwaves.
Shawyer says that his company, Satellite Propulsion Research Ltd., has successfully tested experimental versions of the thruster. But many scientists have dismissed or downplayed such claims, saying the propulsion system violates the law of conservation of momentum, Wired UK reported.
In 2012, however, a team of Chinese researchers built their own version of the system and found that it does indeed work, generating enough thrust to potentially power a satellite. Then, an American scientist named Guido Fetta constructed his own device, which he calls the "Cannae Drive," and convinced the NASA team — which included warp drive researcher Sonny White — to try it out, which they did over the course of eight days in August 2013.
The NASA scientists determined that the Cannae Drive produces 30 to 50 micronewtons of thrust — less than 0.1 percent of that measured by the Chinese team, Wired UK noted, but nevertheless suggesting that the technology works.
The thruster may work by somehow harnessing the subatomic particles that continuously pop into and out of existence, the NASA researchers suggest. The results and the technology are promising enough to warrant further study, they wrote in the study.
"Future test plans include independent verification and validation at other test facilities," the researchers wrote.
(Excerpt) Read more at space.com ...
Vacuum energy is an underlying background energy that exists in space throughout the entire Universe. One contribution to the vacuum energy may be from virtual particles which are thought to be particle pairs that blink into existence and then annihilate in a timespan too short to observe. They are expected to do this everywhere, throughout the Universe. Their behavior is codified in Heisenberg's energy–time uncertainty principle. Still, the exact effect of such fleeting bits of energy is difficult to quantify.
The effects of vacuum energy can be experimentally observed in various phenomena such as spontaneous emission, the Casimir effect and the Lamb shift, and are thought to influence the behavior of the Universe on cosmological scales. Using the upper limit of the cosmological constant, the vacuum energy in a cubic meter of free space has been estimated to be 10−9 joules (10-2 ergs).[1] However, in both Quantum Electrodynamics (QED) and Stochastic Electrodynamics (SED), consistency with the principle of Lorentz covariance and with the magnitude of the Planck constant requires it to have a much larger value of 10113 joules per cubic meter.[2][3] This huge discrepancy is known as the vacuum catastrophe.
http://en.wikipedia.org/wiki/Vacuum_energy
How about if it runs on dead mooselimbs?
Certainly interesting.
But still apparently mysterious. They claim it’s making use of vacuum energy released by some sort of interaction between virtual particles and microwave photons.
Very mysterious but something that could be truly revolutionary and definitely worthy of further research.
Thanks for the link. Unfortunaely, this is one of those areas where one really does need to be a rocket scientist to fully understand. :)
I was commenting about electric propulsion in general and microwaves in particular, but what you say is true. Some of the terminology used in the space.com article is strange indeed (”chamber,” no “propellent,” etc.).
Improbability drive?
50 micronewtons is about 2/10,000 of an ounce of force.
Almost enough to blow away a mosquito.
And the Ion propulsion we use on some spacecraft now has about enough force to lift a single sheet of notebook paper.
Not designed for drag racing but given enough time they can achieve significant speeds.
About 0.15oz? (this old brain does not think well in micronewtons)
About 800 times more powerful than the experimental engine under discussion?
In particular, they also had a "control" device (the report refers to it as a "null" device) that was specifically built to not produce any thrust. The test setup measured thrust from the "null" device. Therefore, they weren't actually measuring what they claimed to be measuring.
Well one is in actual use and the other is being tested on a small scale.
BTW despite the claim that this is the same as Ion propulsion up thread, Ion drives actually do need to carry fuel. They use argon gas I believe.
http://en.wikipedia.org/wiki/Roger_Shawyer
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EmDrive (also RF resonant cavity thruster) is a spacecraft propulsion system proposed by British aerospace engineer Roger J. Shawyer, who develops prototypes at Satellite Propulsion Research Ltd (SPR),[1] the company he created for that purpose in 2000.[2] New Scientist ran a cover story on EmDrive in its 8 September 2006 issue.[3] The device uses a magnetron producing microwaves directed inside a specially shaped, fully enclosed tapering high Q resonant cavity whose area is greater at one end and having a dielectric resonator in front of the narrow end. The inventor claims that the device generates a thrust even though no detectable energy leaves the device. The engine does not require any reaction mass although an outside energy input (fuel, solar or nuclear) is still required. If proven to work as claimed, it would be a breakthrough in all forms of travel including ground travel, marine travel, sub-marine travel, airflight and spaceflight.[4][5][6][7][8][9]
The device, its mode of operation, and theories attempting to explain it are all controversial. As of 2014[update], there are still arguments about whether the EmDrive is a genuinely new propulsion method, or a misinterpretation of spurious effects mixed with mathematical errors. The proposed theory was quickly criticised because it seems to violate conservation of momentum, a fundamental law of physics, though the inventor insists it does not.[10]
Chinese researchers from the Northwestern Polytechnical University (NWPU) in Xi'an first claimed to replicate the experiment in 2010,[7][11][12][13] though they were also clear that their work was still preliminary. Then at the Johnson Space Center in 2014 a group also claimed a replication.[9][14]
Static thrust tests:
Shawyer claims to have undergone seven independent positive reviews from experts at BAE Systems, EADS Astrium, Siemens and the IEE.[15] As of 2014, no EmDrive has been tested in microgravity.
Shawyer, in 2006, claimed that commercial terrestrial aircrafts incorporating EmDrives as lift engines could be ready by 2020,[16][17] through very high Q superconducting resonant cavities that would allow static specific thrusts of about 30 kN/kW, that is 3 tonnes of thrust per kilowatt of input power, "enough to lift a large car".[18]
New Scientist article:
After receiving criticism that no peer-reviewed publications on the subject had been made, Shawyer submitted a theory paper to New Scientist, a weekly science magazine which is not a peer-reviewed scientific journal.[19] The EmDrive was consequently featured on the cover of the 8 September 2006 issue of the magazine. The article portrayed the device as plausible, and emphasized the arguments of those who held that point of view.
Science fiction writer Greg Egan distributed a public letter stating that "a sensationalist bent and a lack of basic knowledge by its writers" made the magazine's coverage unreliable, sufficient "to constitute a real threat to the public understanding of science". In particular, Egan found himself "gobsmacked by the level of scientific illiteracy" in the magazine's coverage of the EmDrive, and alleged that New Scientist employed "meaningless double-talk" to obfuscate the relation of Shawyer's proposed space drive to the principle of conservation of momentum.
Egan urged those reading his letter to write to New Scientist and pressure the magazine to raise its standards, instead of "squandering the opportunity that the magazine's circulation and prestige provides" for genuine science education. The letter was endorsed by mathematical physicist John C. Baez and posted on his blog.[20][21]
Egan also recommended[20] that New Scientist publish a refutation penned by John P. Costella (a data scientist with a PhD in theoretical physics)[22] of Shawyer's paper.[19]
The following month, the New Scientist editor addressed the ensuing controversy over the article stating that "We should have made more explicit where it apparently contravenes the laws of nature and reported that several physicists declined to comment on the device because they thought it too contentious."[23
Replication claims:
Chinese Northwestern Polytechnical University (NWPU):
In 2008, Wired magazine reported that a team of Chinese researchers led by Juan Yang (杨涓), professor of propulsion theory and engineering of aeronautics and astronautics at Northwestern Polytechnical University (NWPU) in Xi'an, claimed to have confirmed the theory behind the drive.[4][24] Their demonstration version of the drive was built and tested at high power in 2010.[11] A maximum thrust of 720 mN was measured at 2500 W of input power on an aerospace engine test stand usually used to precisely test spacecraft engines like ion drives.[8][25][12][13]
The editor of Wired magazine who covered the experimental results relating to reactionless drives reported that he received some comments from the Chinese researchers stating "the publicity was very unwelcome, especially any suggestion that there might be a military application"[6] and that Yang told him that "she is not able to discuss her work until more results are published".[8]
NASA/JSC Advanced Propulsion Physics Laboratory:
A NASA team at the Advanced Propulsion Physics Laboratory (informally known as Eagleworks)[26] located at the Johnson Space Center (JSC) under the guidance of physicist Harold G. White is devoted to studying advanced propulsion systems that they hope to develop using quantum vacuum and spacetime engineering. The group has investigated a wide range of fringe proposals including the EmDrive, and related concepts listed below.
RF resonant tapered cavity thruster (EmDrive): In July 2014, the group reported on an evaluation of a RF resonant tapered cavity similar to Shawyer's EmDrive, with positive results.[14] Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a sealed stainless steel vacuum chamber, but at ambient atmospheric pressure, because the RF power amplifier used an electrolytic capacitor not capable of operating in hard vacuum.[14]
NASA's tests of the tapered RF cavity were conducted at very low power (50 times less than Shawyer's 2002 experiment and 150 times less than the Chinese 2010 experiment) but a net mean thrust over five runs was measured at 91.2 µN at 17 W of input power. A net peak thrust was recorded at 116 µN at the same power level.[14]
The experiment has been criticized for not having been performed in a vacuum, potentially allowing air currents to compromise results,[27] although tests were performed at about a hundred-millionth of normal atmospheric pressure.[28]
In the coming months, Eagleworks plans to upgrade their equipment to higher power levels, use vacuum-capable RF amplifiers with power ranges of up to 125 W, and design a new tapered cavity analytically determined to be in the 0.1 N/kW region. Then, the test article will be shipped to other laboratories for independent verification and validation of the technology, at Glenn Research Center, the Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory.[14]
Cannae drive:
The same NASA test campaign also evaluated another unconventional propulsion test article known as the Cannae drive (formerly Q-drive)[14] which is also an asymmetric but flatter resonant cavity invented by Guido P. Fetta, CEO of Cannae LLC,[29] a company located in Pennsylvania, who filed two patent applications[30][31] and presented a paper at the same conference.[32] Shawyer noted that the Cannae drive "operates along similar lines to EmDrive, except that the asymmetric force derives from a reduced reflection coefficient at one end plate" but also stated this design "degrades the Q and hence the specific thrust that can be obtained".[9]
Eagleworks tested two versions of the Cannae drive: a thruster test article with radial slots engraved along the bottom rim of the resonant cavity interior, as required by Fetta's theory to produce thrust;[29] and a "null" test article lacking those radial slots. Both drives were equipped with an internal dielectric.[14] The null test was not intended as the experimental control, which was a third test article involving an RF load without the resonant cavity interior.[27] Like the EmDrive tests, these took place at atmospheric pressure, not in a vacuum.
According to the technical report, both Cannae drives (the standard and the null test articles) produced net thrust. The experimental control measured zero thrust.[27] Some consider the positive result for the slotted article as indicating a possible flaw in the experiment, as the null test article had been expected to produce no thrust.[33][34][27] In the complete paper, Eagleworks concluded this behavior proved "thrust production was not dependent upon the slotting".[14]
Theory:
Any apparent reactionless drive is treated with skepticism by the physics community, because a truly reactionless drive would violate the principle of conservation of momentum. Shawyer claims that his drive does not violate conservation of momentum and is not reactionless.[10] Shawyer has published an updated theory paper (version 9.4) for the EmDrive.[35]
Various theories have been proposed explaining the underlying physics for how the EmDrive might produce thrust. Shawyer claims the thrust would be caused by radiation pressure imbalance between the two faces of the cavity caused by the action of group velocity in different frames of reference, within the framework of special relativity.[36] Yang from NWPU predicts a resulting net force using classical electromagnetism.[13] Harold G. "Sonny" White, who investigates field propulsion at Eagleworks, NASA's Advanced Propulsion Physics Laboratory, notes that such resonant cavities may operate by creating a virtual plasma toroid that would realize net thrust using magnetohydrodynamics upon quantum vacuum fluctuations.[37]
Likewise, the paper describing the Eagleworks test of the Cannae drive referred to a possible interaction with "quantum vacuum virtual plasma".[14] This reference has been criticized by mathematical physicists John Baez and Sean M. Carroll because the standard description of vacuum fluctuations do not behave as a plasma.[38][39]
http://en.wikipedia.org/wiki/EmDrive
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Also see,
EM Drive.com:
http://www.emdrive.com/
What Is A Solar Sail?
by Fraser Cain on January 20, 2014
Here’s how they work: Light is made up of photons. Even though they have no mass at rest, they have momentum when they’re moving, well, light speed. When they reflect off a surface, like a mirror or a shiny piece of metal, they impart some of this momentum to that surface. This effect is negligible here on Earth, but out in space, with forces perfectly in balance, that additional momentum can really add up.
A spacecraft flying to Mars gets pushed off course by several thousand kilometers because of light pressure from the Sun.If mission planners didn’t compensate for this drift, their spacecraft would miss the planet, or even worse, crash into it. Even though the total amount of pressure per square meter on a solar sail is minuscule, it’s constantly streaming from the Sun, and it’s totally free….
And propulsion that you don’t have to carry with you is the best kind there is.
IKAROS – solar sail from Japan. Image: JAXA
This is more than just an idea. Solar sails have already been launched and deployed in space. The Japanese Ikaros satellite unfurled a 14-meter solar sail back in 2010. NASA launched its own Nanosail-D spacecraft in 2011. An even bigger solar sail, the Sunjammer, is planned for launch in 2014. The Planetary Society is working on a solar sail project as well.
http://www.universetoday.com/108310/what-is-a-solar-sail/
The Kepler space telescope has been kept working to so extent using solar pressure. Its not working the way it was intended but they are able to use it by orienting it with solar pressure.
Dr McKay had better success but accidently blew up a solar system.
[Stargate Atlantis}
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