Category Archives: accommodation

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.

 

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Ultra-tall structures – from ground into space

I was 8 when Armstrong and Aldrin set foot on the moon. It was exciting. My daughter is 18 and has never witnessed anything of the same order of excitement. The human genome project was comparable in some ways but lacked the Buzz.

There is excitement about going back now. We will, and on to Mars. We can do space so much more safely now than back in the 60s.  Commercial companies are pioneering space tourism and later on will pioneer the mining bits. But the excitement recently is over the space elevator. The idea is that a cable can stretch all the way from the surface out into space, balanced by gravity, and used as a means to cart stuff back and forth instead of having to use rockets, making it easier, less expensive and less dangerous.

It will happen eventually on Earth. We need to make new materials that are strong enough. Carbon nanotube cables and other fancy materials will be needed that we can’t make long and strong enough yet. But the moon has lower gravity so it is much easier there and will likely happen earlier.

There are plenty of web articles about space elevators already so I don’t need to repeat everything here. But a space elevator is supported from above, a regular building is supported from below. How can we build one very tall from the ground?

I recently issued a report on 2045 construction that among other things also discussed spaceports up to 30km tall:

https://timeguide.wordpress.com/2015/10/21/2045-constructing-the-future/

A 30km tall spaceport on Earth could make use of atmospheric buoyancy for the lower end which of course we wouldn’t get on the moon for the spaceport coming home, but we also wouldn’t get wind on the moon to add stresses. On the moon gravity is less so the structure could be much taller. On the moon a graphene structure could form as much as the bottom 150-200km of the climb. It might offer a nice synergy. The diagram above shows some of the possible structure for the columns, biomimetically inspired by plant stems, though this is just one suggestions, and there are very many ways they could be designed.

This could be enhanced by filling columns with graphene foam:

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

Since I wrote that, carbon foams have been made and they are 6 times lighter than air.

So how about a 30km tall building? Using multilayered columns using rolled up or rippled graphene and nanotubes, in various patterned cross sections, it should be possible to make strong threads, ribbons and membranes, interwoven to make columns and arrange them into an extremely tall pyramid.

This could be used to make super-tall structures for science and tourism or spaceports, or a home for celebrities, well out of sight of the Paparazzi.

Think of a structure like the wood and bark of a tree, with the many tubular fine structures. Engineering can take the ideas nature gives us and optimise them using synthetic materials. Graphene and carbon nanotubes will become routine architectural materials in due course. Many mesh designs and composites will be possible, and layering these to make threads, columns, cross members with various micro-structures will enable extremely strong columns to be made. If the outer layer is coated to withstand vacuum, then it will be possible to make the columns strong enough to withstand atmospheric pressure, but with an overall density the same as the surrounding air or less. Pressure is of course less of an issue higher up, so higher parts of the columns can therefore be lighter still.

We should be able to make zero weight structures in the lower atmosphere, and still have atmospheric buoyancy supporting some of the weight as altitude increases. Once buoyancy fails, the structure will have to be supported by the structure below, limiting the final achievable height.  Optimising the structures to give just enough strength at the various heights, with optimised mesh structure and maximal use of buoyancy, will enable the tallest possible structures. Very tall structures indeed could be made.

So, think of making such a structure, with three columns in a triangular cross-section meeting at 43 degrees at the top (I recall once calculating that is the optimal angle for the strongest A frame in terms of load-bearing to weight ratio, though it ignores buoyancy effects, so ‘needs more work’.

30km tall structures would not be ideal for large scale habitation, since much of the strength in the structure would be to support the upper parts of the structure itself and whatever platform loading is needed. But for a celebrity home, small military observation base or a decent sized lab, it might be fine. The idea may be perfect for pressurised platforms at the top for scientific research, environmental monitoring, telescopes, space launches, tourism and so on. The extreme difference in temperature may have energy production uses too.

Getting the first 30km off the ground without needing any rocket fuel would greatly reduce space development costs, not to mention carbon and high altitude water emissions.

A simple addition to this would be to add balloons to the columns at various points to add extra buoyancy, but they cannot give much extra lift once the atmosphere is too thin so probably wouldn’t make much difference.

Nevertheless, the physics limits are pretty good. 30km is a reasonably achievable goal for a 2045 spaceport, but given the known strength of graphene and carbon nanotubes, a 600km tall building on Earth would be the limit, and that is higher than the Hubble telescope!