[AR] Re: NASA test of quantum vacuum plasma thruster
- From: Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sat, 09 Aug 2014 09:51:12 -0700
On 8/7/2014 2:49 PM, Paul Breed wrote:
Wired on the topic:
http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive
Well, that seemed to quiet things down a bit... Worth reading, for
anyone who hasn't. It's short, and it clears up a number of points that
were unclear or downright confused in the abstract and early news reports.
Some points they cover:
They don't entirely refute John S's point about the dangers of
inexperienced operators using a precision mechanism just above its noise
threshold, but they do:
- give somewhat more detail on the test setup
- mention at least one result with a different device considerably
further above the noise floor: "4. Why didn't they test Shawyer's
EmDrive design as well as the Cannae drive?
"It turns out that in January this year they did test the EmDrive design.
"The test results for this were also positive, and in fact their
tapered-cavity drive, derived from the Chinese drive which is in turn
based on Shawyer's EmDrive, produced 91 micronewtons of thrust for 17
watts of power, compared to the 40 micronewtons of thrust from 28 watts
for the Cannae drive."
- mention that the abstract is in error and (some?) tests were done in
vacuum after all: "While the original abstract says that tests were run
"within a stainless steel vacuum chamber with the door closed but at
ambient atmospheric pressure", the full report describes tests in which
turbo vacuum pumps were used to evacuate the test chamber to a pressure
of five millionths of a Torr, or about a hundred-millionth of normal
atmospheric pressure." (HV - Note that it's still left unclear from
this wording whether ALL tests were done in vacuum.)
They also clarify the matter of the "Null Drive" that also showed
thrust, a widely misunderstood point. This was actually a design
variation that by one theory would not produce thrust; it showed thrust
anyway, thus disproving that one theory. When they tested with a simple
resistive load as their actual control, they in fact showed no thrust.
Also, when they reversed the "drive" device orientation, the measured
thrust also reversed.
Assuming these tests were actually done in vacuum, I'd say the odds of
something interesting being there just got considerably better.
My take: It's not at all clear to me that this obviously is just some
mix of wishful thinking, experimental error, and possibly even fraud. It
looks like there *may* be an actual reproducible effect here.
What it actually is, what the physics behind it actually are, what it
may end up being useful for, all should await more data. Which,
presumably, multiple competent groups are right now working on getting.
Me, I'd be particularly interested in the results from a few quickie
cubesats with one of these devices onboard, launched, allowed to outgas
thoroughly, precision-tracked, then activated.
Henry
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