AZoNetwork recently attended a lecture given by Adrian Nixon and Peter Robinson on 27th February 2018 at Manchester Metropolitan University, about Space Elevators and the work of the International Space Elevator Consortium. The following article is based on the presentation they made.
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Launching a rocket into space is a risky and expensive undertaking, not to mention very wasteful. So as a way to address all of these costs and challenges associated with rocket transport, various groups around the world are currently working on a concept known as a space elevator.
A space elevator aims to do exactly what the name suggests; move goods and people high up into space. Such a system would connect a ground- or sea-level station to another location in geosynchronous orbit. It would do so much more safely than a rocket, at a fraction of the cost and with zero pollution in the process.
By making travel into orbit routine and cheap, space elevators would make all kinds of space-based endeavors much more feasible; from colonizing Mars to asteroid mining. A space elevator system could also facilitate research, help generate solar power, provide shade from the sun and lower the cost of space tourism.
A 100,000-km tether anchored to the Earth would be extended out into space, where it is attached to the apex anchor, which could be a large space station or even an asteroid. Centrifugal force would then make the tether taut, and mechanical climbing vehicles would be able to travel up and down it. On a smaller scale, similar theoretical physics occur if you tie a string around a ball and then swing that ball around your head.
The Earth-based anchor of a space elevator would be more than just a structure built to secure the system to the Earth. This terminus would include both the anchor itself and an operations platform that could be used for commerce, administration, and logistics.
The tether would be around 100,000 km long and 1 meter wide. Created from an ultra-strong material such as graphene or carbon nanotubes, the tether would have to be capable of supporting seven concurrent climbers of 20 metric tons each, including 14 metric tons of payload.
As noted above, the apex anchor could be a man-made space station, or it could be an asteroid. It would have to be sufficiently weighty and would be traveling at speed.
Making the Tether
The biggest engineering obstacle we are faced with when making an operational space elevator is developing a viable tether, as long lengths of high strength material are required.
While carbon nanotubes have long been considered a serious contender, it now appears that graphene is a more viable solution, thanks to a recent breakthrough. Two hundred times stronger than steel and 100 times more resistant to tearing, graphene’s qualities could well make it an ideal tether material.
However, conventional production methods are currently incapable of making a graphene sheet long enough to create a tether. The top-down process, which involves making graphene from graphite, produces nanoplatelets that cannot be seamlessly connected. The bottom-up method, which involves a process called chemical vapor deposition, produces graphene with crystal-grain boundaries and discontinuities.
In an exciting development, a study published last year on single-crystal graphene could open the door to a graphene tether. Published by a team of Chinese researchers, the study described how a large sheet of copper foil and specific growing conditions could be used to form a single sheet of continuous graphene with 99 percent ultra-highly oriented grains forming a single crystal.
The Business of Space Elevators
The development of space elevator technology would spark all manner of new business and even new industries.
Firstly, the development of tether-quality graphene would allow for improvements on everything from touchscreen technology to data security, to high-rise construction. The person or business that brings this quality of graphene to market would likely be able to generate enough income to fund the creation of a space elevator all on its own.
Once a space elevator is built, it would enable all kinds of new businesses that might take people to Mars or mine asteroids for precious metals. A study by the International Academy of Aeronautics found a space elevator would realize a 100 percent return on investment after about 10 years.
Creating a space elevator is a difficult task, and it will cost a lot of money. However, experts say it is likely to happen within the next 40 to 50 years. In fact, some simulations have already been built, although much more comprehensive designs are planned in the future. A few short tethers of approximately 100 meters have also been trialed in orbit by the Japanese Space Agency (JAXA), to examine the effects of hazards and radiation.
The process would start with a working concept and startup phase, where engineers would create dynamic simulation models to address challenges such as space debris, lightning strikes, and climbers design. In the prototype and testing stages, engineers would create small-scale systems, possibly on large asteroids such as Vesta, Psyche or Eros. Psyche remains the most promising as it has a high rotation rate and is very metallic; making it attractive to asteroid miners. The tethers on these small-scale models would range from less than 100 km to 1000 km and more.
After modeling and prototype phases have led to a plan and a high degree of confidence, work could begin on a full-scale Earth-based space elevator. Current projections have that becoming operational around 2060.