Dean drive

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The Dean drive or Dean device is a hypothetical scheme for spacecraft propulsion. The patent is of a variety known as an oscillation thruster.

It is named after Norman L. Dean, who called it a reactionless drive and who patented an alleged example of such a device. According to Dean, his propulsion device can produce linear acceleration without the use of any reaction mass. If such a device could be physically realized, it would revolutionize space travel, since in conventional rocketry most of a rocket’s launch weight is devoted to carrying mass that is ejected downwards to drive the remaining mass of the rocket and its payload upwards. A reactionless drive would violate Newtonian physics, and is regarded by the scientific mainstream as physically impossible.

[edit] Role of John W. Campbell

The Dean drive obtained a good deal of publicity in the 1950s and 1960s via the columns of John W. Campbell, the longtime editor of Astounding Science Fiction magazine. Campbell apparently believed that the device worked and claimed to have witnessed it operating on a bathroom scale. The weight reading on the scale appeared to decrease when the device was activated. He subsequently published photographs of the scale with the drive stopped and running. The June 1960 cover of Astounding magazine featured a painting of a United States submarine orbiting Mars, supposedly propelled there by a Dean drive.

Dean, who was trying to find potential buyers for his technology, was secretive about the details of how it was supposed to work, but it was said to contain asymmetrical rotating weights and to generate a great deal of vibration.

Dean and Campbell claimed that Newton’s laws of motion were only an approximation, and that Dean had discovered a fourth law of motion. This has been described as a nonlinear correction to one of Newton’s laws, which, if correct, would allegedly have rendered a reactionless drive feasible after all.

One result of the initial articles in Campbell's magazine was that two other researchers, William O. Davis and G. Harry Stine, visited Dean and witnessed a demonstration. Results of this visit were published in the May 1962 and June 1976 issues of the magazine, the name of which had been changed by Campbell from "Astounding" to "Analog". Davis' 1962 article was titled, "The Fourth Law of Motion", and described an hypothesis in which Dean's device (and others) could conserve momentum invisibly via "gravitational-inertial radiation" --we would probably just say "gravitational waves", today, although based on the description in the article, we might consider these to have wave-shapes of the "soliton" variety. One detail of the hypothesis involved the forces of Action and Reaction --physical bodies can respond to those forces nonsimultaneously, or "out of phase" with each other. Stine was an engineer who built devices to test that aspect of the hypothesis. In his 1976 article, "Detesters, Phasers and Dean Drives", Stine claimed they were able to reliably create and reproduce a 3-degree phase angle. Their research was terminated when the national economy took a downturn, and was never resumed (the 1976 article was an attempt to get research re-started, but apparently failed).

Skeptics maintain that there are many possibilities for illusory effects, involving interactions of vibration, friction, resonance with the springs of the scale, instantaneous photographs of an oscillating scale reading, and so forth. Some even go so far as to attribute the reported demonstrations to outright deception, either by Dean, by witnesses or both.

[edit] Further developments

Purportedly, several groups (including Westinghouse and the U.S. military) became interested in buying the device, if it worked, for sums of half a million dollars or more. Dean’s paranoia and insistence upon cash before showing the device, kept interested parties from seeing the device, and Dean never did make any sales.

In 1999, Dean’s son, Norman Robert “Bob” Dean, appeared at an anti-gravity conference by invitation of a group of patent holders who had created differing versions of the reactionless drives that referred to N.L. Dean in their patents. He gave a presentation about his father’s device. The original drive models, as well as Dean’s well-kept and detailed notes, are apparently in the possession of the Dean Family.

The noted science-fiction writer and critic Damon Knight had this to say about the Dean drive in a chapter called “Campbell and His Decade” in his collection of essays about the science-fiction field In Search of Wonder:

Oh, the Dean Machine, the Dean Machine,

You put it right in a submarine,

And it flies so high that it can’t be seen—

The wonderful, wonderful Dean Machine!

[edit] Conceptual issues

One major problem with the Dean patent is that the device simply does not appear to work as described. There have been no published reports of attempts to accurately reconstruct and test the device. Most skeptics nevertheless maintain that it can't work even though several eyewitnesses to demonstrations by Dean claim otherwise.

Some claim that this discrepancy is due to intentional omissions in the technical details of the patent disclosure documents - a subtle effort to prevent intellectual property theft. Others deny any possibility that this is the case and maintain that the patented device simply doesn't work. In either case the result is the same, so it makes little difference insofar as replication of Dean's experiments are concerned.

One major argument against the possibility of physically realizing a reactionless drive like the Dean Drive is that such a device could not transfer momentum and thus violates Newtonian physics. New scientific theories such as stochastic electrodynamics [1] might eventually provide an explanation for some mechanisms of momentum transfer not currently encompassed by Newtonian physics. Such a development might reopen the debate on the Dean drive and make it possible to resolve the issue once and for all.

[edit] See also

• Newton’s laws of motion
• Stochastic Electrodynamics (SED), for work in developing physics by Haisch, Rueda, and Puthoff, presenting the concept of an “inertia-modification” drive. The SED Hypothesis has been published in scientific literature but is as yet unproven.
• Reactionless drive, for more about “inertia-modification” devices. Reactionless drives are presently considered a scientific impossibility.

[edit] External links

• Dean Space Drive, a website (apparently maintained by the Dean family) detailing additional materials and background information on Norman Dean and his device.
• Dean Drive and Other Reactionless Drives, a narrative by Jerry Pournelle describing his brief investigation of the Dean Drive.
• Patent 02886976
• Patent 03182517