Unless you’ve been sleeping under a rock, you’ve undoubtedly noticed that a new space race is underway, and I would love to somehow take part in it.
Thrust capacitors might be my way in… 🤞
Rocket propulsion needs an upgrade
The pure epicness of multiple roaring engines blasting jets of fire to lift a rocket into space is still one of the most awe inspiring feats of engineering to behold, but you can hardly call it an ideal form of transportation.
It certainly isn’t efficient, with the average SpaceX Falcon 9 rocket using an astonishing 500,000 kg (!!) of propellant per launch in order to escape Earth’s gravity.
What if we could lift off into space in total silence, without the need for flames, engine roars, and literal tonnes of propellant?
That is precisely what some scientists are promising us; an electric “rocket”.
For the most part, such systems use electric fields, often of high potential, to generate a tiny but consistent force, as has been shown in several labs, research papers [1, 2], and experiments around the world.
And although the acceleration of a system like this is very slow, it can come awfully close to reaching the speed of light if given enough time, reigniting dreams of visiting neighbouring stars within our lifetimes…
Theories on propellantless thrust
To many, the above claims may sound preposterous.
“Uh bro, thrust can’t come out of nowhere!”
Luckily there have been several people way smarter than I am who have thought deeply about possible reasons for this perceived thrust to occur.
Ionic wind
Ion wind is often used as a simple explanation to debunk other, more exotic theories.
Whenever someone shows that a capacitor generates thrust, people are quick to chime in that the effect is simply due to an airflow of charged particles, also known as ionic wind.
To exclude this possibility, it’s crucial to test the system in a vacuum chamber.
Biefield-Brown Effect
In 1920 the inventor Thomas Townsend Brown discovered that if you apply a high voltage to an asymmetrical capacitor, a force is established towards the smaller capacitor plate.
NASA researched this, and came to the conclusion that this phenomenon was caused by the ionic wind we just discussed.
Woodward / Mach Effect
James F. Woodward, a professor at California State, proposed a theory based on Mach’s principle, that mass fluctuations occur in an accelerating object, causing fluctuations in inertia, and that these fluctuations could generate small thrusts without the need for propellant.
This effect has not been conclusively demonstrated as far as I know.
Aether
James Clerk Maxwell, the Scottish scientist famous for the mathematical theory of electromagnetism, believed that electromagnetic waves cannot travel through a vacuum, and so a medium through which the waves travel must exist, which was dubbed the aether.
“It appears therefore that certain phenomena in electricity and magnetism lead to the same conclusion as those of optics, namely, that there is an ethereal medium pervading all bodies, and modified only in degree by their presence; that the parts of this medium are capable of being set in motion by electric currents and magnets; that this motion is communicated from one part of the medium to another by forces arising from the connections of those parts; that under the action of these forces there is a certain yielding depending on the elasticity of these connections; and that therefore energy in two different forms may exist in the medium, the one form being the actual energy of motion of its parts, and the other being the potential energy stored up in the connections, in virtue of their elasticity.” ~ James Clerk Maxwell
Then in 1887 the infamous Michelson–Morley experiment put an end to that theory, at least in the minds of many physicists.
However, there are still many researchers and experimenters, mostly outside of academia, which claim that their often fascinating experimental results can only be explained by the existence of an aether.
Quantised Inertia
Now the most credible, most well researched theory out there has got to be Dr. Mike McCulloch’s Quantised Inertia, or QI.
This ingenious new physical theory gets rid of dark matter, gets rid of the gravitational constant, predicts anomalous behaviour in galaxy rotation, and most excitedly: predicts propellantless rockets!
McCulloch’s research has been funded by DARPA, multiple labs have replicated his results, and a SpaceX rocket has already sent a tiny satellite into space with a QI drive onboard, whose mission was unfortunately cut short when the satellite communication malfunctioned before the drive could be turned on.
This is therefore the theory we will focus our attention on in this article, so let’s see how it works and how QI can be used to build an electric rocket.
How to build an electric rocket
The best person to explain the theory is the inventor, Dr. Mike McCulloch himself, so I strongly recommend you watch his TED talk below.
How I would explain it in layman terms:
When you stand still, you don’t experience inertia because everything around you, including light, is in balance.
When you accelerate in a certain direction, you disturb this balance, as some of the light behind you is no longer able to catch up, as it would have to go the speed of light + your speed, which would break the laws of physics.
This essentially creates some sort of an event horizon behind you, called a Rindler horizon, beyond which nothing can be known, as not even light is able to reach you from beyond that point.
Information is thus “lost” behind you, while the amount of information in front of you remains the same, and because nature always tries to restore balance, you experience a “pressure” from the front, which we call inertia.
The faster you accelerate, the less information will be able to catch up with you, the greater the pressure differential, and thus the greater the inertia experienced.
I’m using terms loosely here to keep it brief, as in reality something called Unruh radiation is at play here, but to learn the finer details of this fascinating theory, I recommend you read McCulloch’s papers and his books.
Cool, but how will this help us build an electric rocket?! 🤓
Say we have a humble parallel plate capacitor consisting of two copper plates separated by a thin dielectric.
If we apply a voltage to make electrons jump from one plate to the other, they will do so at close to the speed of light, and so by QI, will experience an inertial force due to the pressure imbalance caused by the acceleration.
The conducting plates act like artificial ‘horizons’ that modify this quantum effect, and this manifests as a minuscule force that will ever so lightly nudge the capacitor in the direction the electron was travelling.
Clearly not nearly enough force to escape earth’s gravity, but we’ll talk about how to increase this force to usable levels in a minute.
However, because this force is so tiny and hard to observe or misdiagnose, I want to briefly cover some basic tips to measure this curious phenomenon.
How to verify results
There are basically 4 ways to verify results of this nature:
1. Launch a prototype into space
See if you can achieve any changes in velocity (ΔV) in the vacuum of space.
While probably the most convincing demonstration possible, it is blatantly obvious that not many people have the funds to go down this route.
IVO ltd. gave it an honest go, and will try again in Feb 2025, but unfortunately their first satellite broke down before they could turn their device on.
2. Precision scale
Using a microgram (0.001) scale you’ll be able to measure the QI thrust of a small parallel plate capacitor.
It is however very easy to mess these measurement up due to:
- Air flow
Ionic wind or a simple draft can make your readings inaccurate, so ideally test in a vacuum chamber, or at the very least place a (transparent) container around your setup. - Electromagnetic interference
High voltage on the capacitor can disrupt the scale’s circuit, so place the capacitor on a 20cm or taller non-conductive stand. - Movement
At the microgram scale, ANY movement shows up in your results, even the slight expansion of the conductors caused by heating due to the current flow through them. So consider using galinstan (room-temperature liquid metal) to exclude the influence of the lead wires from your measurements, or even try to charge the capacitor wirelessly, like Nikola Tesla did.
3. Rotating setup
If you’re able to create an ultra low friction rotating mechanism, perhaps using a tungsten needle point or a magnetic bearing, the tiny amount of thrust might result in a slowly accelerating rotating motion.
This is not an easy feat to pull off, as you’ll also somehow have to provide power to your capacitors while it rotates.
4. Pendulum
A pendulum improves upon the fickle measurements of the microgram scale and is much easier to setup than a rotating mechanism.
IVO ltd. also used pendulums inside a vacuum chamber in order to test their Quantum Drive before launch.
By using a pendulum setup, we no longer have to worry about electromagnetic interference or tiny movements, especially if we build one of a reasonable size like IVO did.
Use a camera closeup, like this guy, or ideally a laser to measure the angular displacement of the capacitor, after which you can use the following formula to determine the force that was applied to achieve the displacement:
F = -m × g × sin(θ)
Where:
F = Force in Newton
m = Mass in kilograms
g = The acceleration due to gravity (~9.81 m/s²)
θ = The angle in radiansYou can make the displacement more pronounced by increasing the length of the pendulum, as it means a smaller angle vs. gravity is required for each unit of horizontal translation.
Ways to increase thrust
While even tiny forces can be enough to move an object in the vacuum of space, it makes measuring these forces accurately back here on earth a very tricky endeavour.
It might therefore help to increase the thrust, so it’s easier to measure, and so that the effect is more pronounced and harder to deny.
The simple formula for estimating thrust from a capacitor according to Quantised Inertia is as follows:
F = 0.00014IA / d2
Where:
F = Force in Newton
I = Current in Amps
A = Plate area in M2
d = Distance between plates in MThis gives us 3 ways to increase thrust:
- Increase capacitor plate surface area
- Increase current flow
- Decrease plate spacing
While surface area and current flow have a linear relationship to force, decreasing plate spacing is the most potent option, as its effects are exponential.
However, thinner dielectrics can withstand less voltage, and, as I’ve found out the hard way in my own experiments using 6 micron kapton, they often break down and are rather hard to work with.
Another great way to increase thrust is to stack capacitors in series, like in McCulloch’s proposal for an interstellar probe which contains 1000 stacked capacitors.
P.S. Access my free QI thrust calculator spreadsheet here.
Propellantless prototypes
Thanks for sticking around while we laid that theoretical groundwork, but now the fun part starts where we get to see some of these devices in action, so let’s dive in!
Alexey Chekurkov’s pointy capacitor
Whenever you search for “capacitor thrust”, the following video pops up, so I thought I’d give it a brief mention.
Some interesting attraction and repulsion phenomena are shown, but the experimenter believes “it’s an atmospheric gas displacement phenomenon that will not work in a vacuum“, so ion wind related.
Asymmetrical capacitor thruster
Now follows an impressive demonstration of the thrust generated by an asymmetrical capacitor thruster.
Unfortunately for budding space travellers, this device is also powered by ion wind and will therefore not work in the vacuum of space.
Check out this NASA research on asymmetrical capacitors, who came to the same conclusion:
“This current involves charged ions which undergo multiple collisions with air.”
Becker & Bhatt symmetrical capacitor thruster
Now the first to actually demonstrate that a symmetrical, parallel plate capacitor can generate propellantless thrust as predicted by Quantised Inertia (QI), were the engineers Frank Becker and Ankur Bhatt.
McCulloch himself helped them setup their experiments, after which they published a paper in 2018, and applied for a US patent in 2019.
Becker & Bhatt were not only able to show thrust, but also observed the Rindler horizon and its effects by placing metal plates at various distances from the capacitor, which was a huge piece of evidence supporting the QI theory.
The general working principle of the symmetrical capacitor thruster is based on accelerating electrons from one plate to the other at extremely high velocities, where the electrons pass through the dielectric by means of quantum tunnelling.
However, electrons don’t just leave their cosy positions willingly, you have to coerce them with a high voltage to establish field emissions.
Besides a higher voltage, heating the capacitor and roughening its surface helps boost electron emissions and thereby the thrust.
I strongly suggest you read their paper, as it is full of valuable insights.
McCulloch’s setup
After Becker & Bhatt’s successful experiments, their results were reproduced at Plymouth University by Dr. Mike McCulloch, together with engineer Richard Arundal.
What is interesting about his setup is the use of galinstan, a liquid conductor, to make the measurements more accurate by reducing the influence of the lead wires on the scale readings.
Also notice the shield around the setup to minimize inaccuracies due to air flow.
McCulloch wrote an informative paper on symmetrical capacitors, which I highly recommend.
IVO, Ltd. quantum drive
As mentioned earlier in this article, IVO ltd took this concept to a whole new level by significantly increasing the size of the setup, replacing the precision scale with a pendulum, testing everything in a vacuum chamber, and even launching their prototype into space on a Falcon 9 rocket!
However, since IVO ltd is a company, there are not a ton of details available, for example about which dielectric they use, as it’s all proprietary information.
What we do know is that when IVO tested their QI drive that eventually went into space, they achieved an impressive 52 millinewtons (mN) of thrust from just one watt of electricity (!!), and all this from a tiny device weighing only 300 grams!
Master Ivo’s pulsed field propulsion
We just talked about IVO ltd, the company, and now we’ll discuss a DIY researcher who goes by the name of Master Ivo on Youtube; similar sounding names, completely unrelated (honestly, what are the odds?).
In the video below he shows a simple pendulum setup, which is visibly set in motion by shorting the capacitor plates through a spark gap.
While Master Ivo mentions inertia in his video, he believes his results stem from aether displacement, although if you replace “aether” with “Unruh radiation”, this all seems to fit nicely within the Quantised Inertia theory, as you can view Unruh radiation as an observer dependent aether.
There are several features of Master Ivo’s setup that I find an improvement over the QI thrust capacitors described earlier, namely:
- Proper conduction path
This setup does not force a dielectric to act as the electron path, which should greatly increase the reliability of the capacitor, and does away with the need to preheat and roughen up the plates. - Larger currents
The QI drives work on leakage currents in the sub μA range, while this setup empties the entire capacitor in just 30 nanoseconds, so way more electrons are on the move, and so much more thrust can be generated.
A major negative is of course the sparks, as they are lossy, hard to control, and the electrodes of the spark gap will wear out at some point.
This got me thinking… can we achieve similar results with a solid-state setup?
Meet the solid-state pulsed QI drive
My plan is to replicate Master Ivo’s pendulum capacitor setup, but replace his spark gap with a state-of-the-art Gallium Nitride FET.
The major challenge for a solid-state circuit that tries to emulate a spark gap, is that it needs to switch the current incredibly fast.
Luckily I developed an ultra-fast GaN FET driver board for a previous project, which can switch up to 650V in a mere 7ns! (And that was with using only 1 of the 2 gate driver channels 😲)
Instead of thousands of volts, I plan to operate at 500V, mainly due to the limits of the FET, and pulse the capacitor at the natural frequency of the pendulum, to steadily increase its momentum and displacement.
Will this work? I sure hope so, but I’ll have to run the experiment to find out.
What do you think will happen? Let me know in the comments below!
And if you want to be among the first to see the results, be sure to follow me on YouTube here.