Keith may recall my "Weird Fun With Propulsion
<http://jimbowery.blogspot.com/2017/06/weird-fun-with-propulsion.html>"
saga involving an apocryphal reactionless drive, and the connection with
Harry Stine's fascination with "The Fourth Law of Motion" dependent on
asymmetric "Jerk" (a=m/s^3).
I pretty much forgot about this guy until I ran across a relatively recent
paper on high frequency gravity waves
<https://www.sciencedirect.com/science/article/pii/S1875389212025163>
mentioning "third time derivative of mass motion":
Abstract
An apparatus or structure is proposed for generating high-frequency
gravitational waves (HFGWs) between pairs of force–producing elements by
means of the simultaneous production of a *third time derivative of mass
motion* of the pair of force–producing elements.
Unfortunately, the guy is now dead whose purported "reactionless drive"
unambiguously accelerated vertically, to the point that he wanted to apply
to NASA for a permit to launch it into space.
I will say that the frequency he was operating at was about 70,000 Hz in a
relatively small device -- which I never saw let alone saw operate.
On Mon, Feb 4, 2019 at 10:45 AM Keith Henson <hkeithhenson@xxxxxxxxx> wrote:
On Sun, Feb 3, 2019 at 10:07 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sun, 3 Feb 2019, Henry Vanderbilt wrote:
Harry was really nice about it - but I learned a proper skepticism.Exactly. The late lamented Jordin Kare once observed that one red flag
Absent demonstrated unambiguous beyond-all-possible-measurement-errors
no-exhaust net thrust, it's all just hand-waving and wishful thinking.
indicating that people are kidding themselves (or worse) is that nobody
can devise an experiment that converts the marginally-detectable hints of
an effect into something blindingly obvious and inarguable.
You can't argue with the obvious, but the wider consequences of a
working reactionless drive on our concept of physics are staggering.
It's a trivial thought experiment to convert a reactionless drive
(where the force/kW is not modulated by velocity) into a free energy
source.
People have waxed lyrical about how a reactionless drive would cut the
cost of power satellites without realizing that such a drive
repurposed for energy production would eliminate the need for power
satellites entirely.
BTW, if you want a target, the cost to GEO per kg times the kg/kW for
power satellites can't exceed about half of the cost per kW. LCOE
limits that to around $2400/kW, $1200kW/6kg/kW gives $200/kg. There
are tricks with beamed energy and arcjets that will get the LEO to GEO
multiplier down to 2, so a lift cost to LEO of ~$100/kg is where
6kg/kW power satellites would break even. The specific power is not
certain but is very likely to be between 3.5 and 7 kg/kW.
Keith