Category Archives: propulsion

Artificial muscles using folded graphene

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Folded Graphene Concept

Two years ago I wrote a blog on future hosiery where I very briefly mentioned the idea of using folded graphene as synthetic muscles:

https://timeguide.wordpress.com/2015/11/16/the-future-of-nylon-ladder-free-hosiery/

Although I’ve since mentioned it to dozens of journalists, none have picked up on it, so now that soft robotics and artificial muscles are in the news, I guess it’s about time I wrote it up myself, before someone else claims the idea. I don’t want to see an MIT article about how they have just invented it.

The above pic gives the general idea. Graphene comes in insulating or conductive forms, so it will be possible to make sheets covered with tiny conducting graphene electromagnet coils that can be switched individually to either polarity and generate strong magnetic forces that pull or push as required. That makes it ideal for a synthetic muscle, given the potential scale. With 1.5nm-thick layers that could be anything from sub-micron up to metres wide, this will allow thin fibres and yarns to make muscles or shape change fabrics all the way up to springs or cherry-picker style platforms, using many such structures. Current can be switched on and off or reversed very rapidly, to make continuous forces or vibrations, with frequency response depending on application – engineering can use whatever scales are needed. Natural muscles are limited to 250Hz, but graphene synthetic muscles should be able to go to MHz.

Uses vary from high-rise rescue, through construction and maintenance, to space launch. Since the forces are entirely electromagnetic, they could be switched very rapidly to respond to any buckling, offering high stabilisation.

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The extreme difference in dimensions between folded and opened state mean that an extremely thin force mat made up of many of these cherry-picker structures could be made to fill almost any space and apply force to it. One application that springs to mind is rescues, such as after earthquakes have caused buildings to collapse. A sheet could quickly apply pressure to prize apart pieces of rubble regardless of size and orientation. It could alternatively be used for systems for rescuing people from tall buildings, fracking or many other applications.

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It would be possible to make large membranes for a wide variety of purposes that can change shape and thickness at any point, very rapidly.

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One such use is a ‘jellyfish’, complete with stinging cells that could travel around in even very thin atmospheres all by itself. Upper surfaces could harvest solar power to power compression waves that create thrust. This offers use for space exploration on other planets, but also has uses on Earth of course, from surveillance and power generation, through missile defense systems or self-positioning parachutes that may be used for my other invention, the Pythagoras Sling. That allows a totally rocket-free space launch capability with rapid re-use.

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Much thinner membranes are also possible, as shown here, especially suited for rapid deployment missile defense systems:

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Also particularly suited to space exploration o other planets or moons, is the worm, often cited for such purposes. This could easily be constructed using folded graphene, and again for rescue or military use, could come with assorted tools or lethal weapons built in.

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A larger scale cherry-picker style build could make ejector seats, elevation platforms or winches, either pushing or pulling a payload – each has its merits for particular types of application.  Expansion or contraction could be extremely rapid.

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An extreme form for space launch is the zip-winch, below. With many layers just 1.5nm thick, expanding to 20cm for each such layer, a 1000km winch cable could accelerate a payload rapidly as it compresses to just 7.5mm thick!

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Very many more configurations and uses are feasible of course, this blog just gives a few ideas. I’ll finish with a highlight I didn’t have time to draw up yet: small particles could be made housing a short length of folded graphene. Since individual magnets can be addressed and controlled, that enables magnetic powders with particles that can change both their shape and the magnetism of individual coils. Precision magnetic fields is one application, shape changing magnets another. The most exciting though is that this allows a whole new engineering field, mixing hydraulics with precision magnetics and shape changing. The powder can even create its own chambers, pistons, pumps and so on. Electromagnetic thrusters for ships are already out there, and those same thrust mechanisms could be used to manipulate powder particles too, but this allows for completely dry hydraulics, with particles that can individually behave actively or  passively.

Fun!

 

 

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Using Inverse Rail Guns for assisted space launch

Following on from the last article on skyline hypersonic travel, Carbon Devices will shortly announce a future space launch system with variants covering a wide range of capabilities. These will range from ultra-cheap launch of lightweight satellites into sub-orbital trajectories up to full orbital launch of large satellites or spacecraft with human crews. The system relies on novel carbon materials only in development today, but that will be routinely available in a decade or two. Once they are, this new system will offer space launches orders of magnitude cheaper and safer than current space launch systems and avoid the environmentally damaging emissions or water vapour in the high atmosphere associated with primitive rocket technology. With far lower launch costs and improved safety, the space industry will flourish.

In the next few posts, several inventions will be disclosed that may be used in our launch systems and weapons. In this article, we explain the first of those, a new technique for driving a tape through a motor at high speed using only electricity. It is related to the rail gun, currently the highest powered artillery system in action, with today’s guns able to launch 10kg metal slugs at over 2km/s, with energy of around 32MJ. By comparison, the Carbon Devices inverse rail gun will be able to launch 60kg slugs at over 50km/s and that is just the scaled down land-based variant. If you believe as we do that the route to peace is to talk softly but carry a big stick, then this is one of our big sticks. We need to learn to talk more softly to each other, because future battlefields will use weapons hundreds or thousands of times more powerful than today’s. The gulf between conventional and nuclear weapons will fully close by mid-century. This pic is a crude example of a fairly modest space weapon with a short tape. Even this would have 3TJ energy, about 100,000 times more than today’s rail gun and 0.75 kilotons of TNT equivalent. This version would only work in space but that’s where some battles in future wars will be fought. Anyway, enough about weapons, the best use of this tech is to launch spacecraft, both from space and into space.

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The Carbon Devices inverse rail gun uses exactly the same linear motor principle of the conventional rail gun, with current passing along and between the rails via the ‘slug’, but effectively inverts the idea of a slug by using a continuous tape of engineered graphene, through which high current is passed to generate the pulling magnetic field. As each short segment of the tape is pulled forwards, the rest follows behind, and although the short segment being driven suffers high heating levels due to the high currents involved, new segments of tape are continuously pulled into play as heated segments exit. The tape as a whole will survive because only a small segment at any time is being subjected to high current, but of course the entire length of tape following is accelerated, along with the attached payload. The length of the tape and thus the exit speed achievable is only limited by practicality. The tape drive has a wide range of applications from ultra-high powered rail guns with exit energy hundreds of times that of current weapons, right up to a super-fast multi-motor space system that will one day deliver crew members or supplies such as water or materials to Mars bases in just 5 days, with a launch speed of 800km/s. Even that speed is limited mainly by the slow acceleration forces that humans can cope with. Another variant that fires inert payloads is an asteroid defense system and the achievable speeds for that could be far higher. This pic gives a crude idea of the concept, using many low powered ‘rail gun’ motors.

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This powerful propulsion system is scalable  (the system shown uses multiple motors and a very long string), and exit speed is only limited by the practical size and cost of the system. 800km/s is a sensible compromise size for routine space missions, since the size of the system scales with the square of the exit speed needed. Because of that, it can not be any practical use for interstellar missions, where technology such as light sails offer much greater suitability. Even if used in conjunction with a light sail, it could only knock a few weeks off a 100 year flight time. (For those of you with weapons interests, the Mars commute system carries about 360TJ, or 85 kilotons of TNT energy equivalent, well into nuclear territory. I haven’t bothered to calculate how powerful it would be if militarized instead of running at just 5g acceleration. ‘Very’ is a good enough guess.

In space, the tape will naturally start very cold which will be an advantage, and of course the tape can also be laid out in a long line to avoid assorted mechanical issues. All of that makes high speeds reasonably feasible. On the Earth however, it is very hard to arrange for a tape to be laid out in a long line, and spooling and indeed unspooling speeds present a huge mechanical engineering problem, not least of which is that a spool spinning at high rpm is dangerous in itself. Aerodynamic heating is also a huge issue for ultra-high speeds. Therefore, land-based variants need to be greatly scaled down. A number of people over the years have suggested using rail guns to launch things into space, and heating is always a severely limiting problem. The novel system we will announce isn’t a rail gun launch and neatly circumvents this problem.

Having said that, rail gun space launch is not impossible and we have devised two novel launch variants using the rail gun linear motor principle. Carbon Devices’ graphene foam invention in 2013 outlined a solid foam that could be made lighter than helium, that would be ideal for supporting loads in the high atmosphere. MIT have more recently produced a lightweight 3d-printed matrix that could be used to print larger shells containing only vacuum (and they could even be printed at high altitude to avoid collapse in the high pressure lower atmosphere).

Slide7If circuits for a linear motor are made from graphene and on a graphene substrate, all supported by such floating platforms, then a long, vertical, linear motor could be made and supported in the air that could accelerate a sled with a disposable heat shield front end, holding a rocket. Depending on acceleration tolerable, fairly high speeds can be obtained, and although not fast enough for orbit, would greatly reduce the size of rocket needed to achieve orbit.

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The first variant is entirely vertical. The rocket and crew or satellite payload would be attached to a sled, and the reusable sled would accelerate up the linear motor. With a few system engineering tweaks, it is feasible to make the path at least 35km high, with an exit speed of around 4000mph (1750m/s) for the 5g acceleration launch that is acceptable for astronauts. Although 4000mph is fast, it is no more than a useful starter push for a rocket that needs to reach the 17,500mph of the space station. Additionally, vertical speed is a useful boost, but no use in itself for orbit – a rocket travelling vertically would simply fall back to Earth eventually unless it gets high horizontal speed.

However, our second variant curves the track into a horizontal path at high altitude, again supported along its entire length by floating platforms made from carbon foam.

Slide39Assuming a 150km track, most of which is 35km high, we would have an expensive but reusable launch system that could accelerate humans up to 8600mph (3800m/s), about half way to orbital speed, and that would all be horizontal speed. It is easily possible to engineer the final sections of track to be higher in the atmosphere, and a slight incline would get our rocket out of atmosphere quickly to minimise heating issues, but the main benefit is that most of the high speed happens in the cold and thin high atmosphere. Such as system is feasible and would greatly reduce launch costs for human spacecraft. For a non-human payload, a 150km track can give full orbital speed for payloads that can tolerate in excess of 20g acceleration. Very many fall in that category, so this system could one day be used to achieve a fuel-free orbital launch.

As mentioned, these are only early system designs and forthcoming articles will outline more advanced Carbon Devices systems with greater potential to accelerate space development.

Using carbon to make a Landspeeder or hoverboard

You are probably familiar with Marty McFly’s hovering skateboard and the Star Wars Landspeeder hover-car. How feasible are they? Like most futurists, I get asked about flying cars every week.

Let’s dispose of pedantry first. Flying cars do exist. Some are basically vertical take off planes without the wings, using directed air jets to stay afloat and move. I guess you could use a derivative of that to make a kind of land-speeder. The hovercraft is also a bit Landspeedery, but works differently. Hovercraft are OK, but a Landspeeder floats higher off the ground and without the skirt so it it’s no hovercraft. Well, we’ll see.

Carbon can be used to make a Star Wars Landspeeder or Marty McFly’s hover board from Back to the Future. Both would be almost silent, with no need for messy skirts, fans, or noisy ducted air jet engines, and could looks like the ones in the films. Or you could employ a designer and make one that looks nice instead.

 

Anti-gravity may one day be possible but we don’t know how to do that yet. Conventional wisdom says that either you use noisy ducted air jets or a hovercraft skirt, or else magnetic levitation, as the Landspeeder is meant to be anyway, which can be done but so far needs a special metal track. It couldn’t work on a pavement or side-walk. You can’t use simple magnetic repulsion effects to levitate above concrete or asphalt.

I pointed out a good while ago with my linear induction bicycle lane idea that you could use a McFly style hover-board on it. My daughter’s friends were teasing me about futurists and hoverboards – that’s why.

http://timeguide.wordpress.com/2013/01/30/hover-boards/

That would work. It would be totally silent. However, the Landspeeder didn’t stay on a linear induction mat laid just under the entire desert surface, did it? That would just be silly. If you had a linear induction mat laid under the entire desert surface, you’d put some sort of horse shoes on your camel and it could just glide everywhere at high speed. You wouldn’t need the Landspeeder.

Ignoring conventional wisdom, with some redesign, you can use magnetic levitation to produce a landspeeder or hoverboard that would work on a sidewalk, pavement, road, or even a desert surface. Not water, not the way McFly did anyway. You could also make the hover tanks and everything else that silently hovers near the ground in sci-fi films. And force fields. Sand, asphalt and concrete aren’t made of metal but that doesn’t matter.

Graphene is a really good conductor. Expensive still, but give it a few years and it’ll be everywhere. It is a superb material. With graphene, you can make thin tubes, bigger than carbon nanotubes but still small bore. You could use those to make coils around electron pipes, maybe even the pipes themselves. Electron pipes are particle guides along which you can send any kind of charged particles at high speed, keeping them confined using strong magnetic fields, produced by the coils around the pipe, a mini particle accelerator. I originally invented electron pipes as a high bandwidth (at least 10^22bit/s) upgrade for optical fibre, but they have other uses too such as on-chip interconnect, 3d biomimetic microprinting for things like graphene tubes, space elevator rope and others. In this case, they have two uses.

First you’d use a covering of the pipes on the vehicle underside to inject a strong charge flux into the air beneath the hoverboard (if you’re a sci-fi nut, you could store the energy to do this in a super-capacitor and if you’re really twisted you might even call it a flux capacitor, since it will be used in the system to make this electron flux). The result is a highly charged mass of air. Plasma. So what?

Well, you’d also use some rings of these tubes around the periphery of the vehicle to create a very strong wall of magnetic field beneath the vehicle edge. This would keep the charged air from just diffusing. In addition, you’d direct some of them downwards to create a flow of charged air that would act to repel the air inside, further keeping it confined to a higher depth, or altitude, so you could hover quite a distance off the ground.

As a quick but important aside, you should be able to use it for making layered force fields too, (using layers of separated and repelling layers of charged air. They should resist small forces trying to bend them and would certainly disrupt any currents trying to get through. But maybe they would not be mechanically strong ones. So, not strong enough to stop bullets, but enough to stop or severely disrupt charges from basic plasma weaponry, but there aren’t many of them yet so that isn’t much of a benefit. Anyway… back to the future.

Having done this, you’ll hopefully have a cushion of highly charged air under your vehicle, confined within its circumference, and some basic vents could make up for any small losses. I am guessing this air is probably highly conductive, so it could be used to generate both magnetic and electrostatic forces with the fields produced by all those coils and pipes in the vehicle.

So now, you’d basically have a high-tech, silent electromagnetic hovercraft without a skirt to hold the air in, floating above pretty much any reasonably solid surface, that doesn’t even have to be smooth. It wouldn’t even make very much draft so you wouldn’t be sitting in a dust cloud.

Propulsion would be by using a layer of electron pipes around the edge of the vehicle to thrust particles in any direction, so providing an impulse, reaction and hence movement. The forward-facing and side facing pipes would suck in air to strip the charge off with which to feed the charged air underneath. Remember that little air would be escaping so this would still be silent. Think of the surface as a flat sheet that pushes ionised air through quite fast using purely electromagnetic force.

Plan B would be to use the cover of electron pipes on the underside to create a strong downward air flow that would be smoothed and diffused by pipes doing the side cushion bit. Neither would be visible and spoil the appearance, and smooth flow could still be pretty quiet. I prefer plan A. It’s just neater.

There would be a little noise from the air turbulence created as the air flow for propulsion mixes with other air, but with a totally silent source of the air flow. So basically you’d hear some wind but not much else.

Production of the electron pipes is nicely biomimetic. Packing them closely together in the right pattern (basically the pattern they’d assume naturally if you just picked them up) and feeding carbon atoms with the right charge through them at the right intervals could let you 3D print a continuous sheet of graphene or carbon nanotube. Biomimetic since the tube would grow from the base continuously just like grass. You could even produce an extremely tall skyscraper that way. 30km is a reasonable limit for 2045, but recent figures for graphene strength suggest that structures up to 600km may be theoretically possible by the end of the century.

Could it work. Yes, I think so. I haven’t built a prototype but intuitively it should be feasible. Back to the Future Part 1 takes Marty to Oct 21, 2015. We just passed that and two prototypes hoverboards were available then. Sadly, neither used my technique but a good lab could just about make most and maybe all of this capability any time soon. On the other hand, Star Wars is set very far away and very long ago, so we’re a bit late for that one.

So, feasible, and just a little way in the future. Pretty much the entire vehicle could be carbon based. Carbon fibre and carbon foam would provide most of the structure, graphene windows for streamlining, strength, protection and transparency, graphene and carbon nanotubes for engines, power and levitation.

High altitude balloons using graphene foam

Graphene foam can be made up of tiny spheres of graphene that contain a vacuum. The graphene spheres are large enough that the average density of the graphene and vacuum is less than helium, so I suggested it as a helium substitute. Here is my original article:

http://timeguide.wordpress.com/2013/01/05/could-graphene-foam-be-a-future-helium-substitute/

It wasn’t long after I wrote it that a Chinese group achieved it, and they subsequently discovered it makes an ideal platform for cultivating stem cells, something that hadn’t even crossed my mind. But that’s engineers for you. Someone invents one idea and someone else runs with it and makes something far better. Anyway, graphene foams already exist today that are 6 times lighter than air.

We hear a lot about high altitude balloons being used for communications, e.g. Google’s Loon project. As is the norm for Google, the idea predates their’s considerably, but never mind, at least they are developing it where others left it on the drawing board.

High altitude balloons so far use helium to achieve the low density. In stark contrast, a huge solid balloon could be made out of graphene foam, and it could be lighter than helium yet stronger than steel. Graphene foam is therefore ideal for making solid balloons for a wide range of purposes.

Way above clouds, the top surface of such a balloon would be perfect to produce solar power for use inside, and the lower side is perfect to transmit this to the ground house communications transponders or simply reflect communication signals.

It could be ideal to house a death ray too, but let’s not think about that for now.

A large, solid, strong balloon could act as an excellent base for a wide range of activities, but it could also be mobile, just like an airship. A combination of special carbon motors such as graphene electron pipes directly powered by energy stored in graphene capacitors. These would be charged with solar electricity generated by from the intense sunlight unimpeded by clouds, the movement of a carbon wire through the magnetic field, thermocouples, solar panels, or harnessing power from high altitude winds. They could even use power harvested from hurricanes and tornadoes, saving many lives and a lot of property too:

https://carbondevices.com/2013/08/11/tackling-tornados-and-hurricanes-the-extractor/

Balloons could also used to deal with forest fires, collecting and storing water directly from clouds and dropping it onto the fire. In fact, these highly positive emergency uses may ultimately be the main reason such a large object would be allowed to remain up in the sky unchallenged in spite of its potential misuses (such as acting the role of mother-ship to a fleet of smaller airships or other weapons). With no need for helium, this kind of solid balloon would be much more environmentally friendly than the traditional variety, perfect for sustainability.