Since the dawn of the space age more than six decades ago, there has only been one way to get to the Moon and back: spacecraft. However, a couple of astronomers from the universities of Cambridge and Columbia (USA) claim that we should already be able to transport humans and cargo between Earth and our natural satellite via a kind of high-tech elevator. It is already technologically possible.
The idea of space elevators is not new, we already know that. Visionaries of spaceflight have been talking about them at least since 1895. But Zephyr Penoyre and Emily Sandford envision a system to provide transportation to and from the Moon.
In a study published online in arXiv , experts argue that it is technologically and economically feasible to build such a “lunar space elevator,” which Jerome Pearson first publicly detailed at a conference in 1977 and Yuri Arsutanov in a later article published in 1979.
Followers of science fiction and fringe technology are familiar with the “space elevator” idea, which is pretty much what it sounds like, but the lunar elevator alternative seems less technically impossible.
The origins
The idea of the space elevator, explored in detail by writer Arthur C. Clarke in his novel “The sources of Paradise” is essentially a tower so high that reaches space. It’s a curious idea, but the simple fact is that this tower would need to be so strong to support its own weight, and that of the counterweight at the other end also so heavy, that no known or even reasonably hypothetical material will do it. Not even remotely.
Could we make a space elevator today?
The key, it seems, is to abandon the whole concept of anchoring the space elevator to the surface of the Earth. Instead, experts propose a tower or cable that extends in the other direction: from the surface of the Moon to the geosynchronous orbit around the planet.
Unsurprisingly, this idea has been presented before, as early as the 1970s. But as they explain: “We present the derivations as a complete and independent mathematical and physical description of the concept, one that we and the authors before us we have been surprised to find and it is eminently plausible and may have been overlooked as an important step in developing our ability as a species to move within our solar system. “
In other words, others have suggested it before, but they have done the math . And it would work. And it would only cost a few billion dollars.
The spatial line would be more like a celestial hook than a tower. A thin, strong piece of material that would extend approximately 362,000 kilometers from the Moon’s surface to a safe distance above the planet, where it would not interfere with satellites or run into the atmosphere.
Anyone interested in going to the Moon would simply be thrown to the correct height of the orbit and synchronized with the tip of the space line , where there would undoubtedly be a station of some kind. From there, they could use solar-powered propulsion to glide along the line, without the need for fuel. At the other extreme, you would simply have to slow down for a soft landing in lunar orbit or whatever surface facility is built there.
Importantly, the space line would pass through the Earth-Moon Lagrange point , where there is effectively zero gravity and no other physical interference, making construction and storage instantaneous.
Having a small team of scientists and engineers in said base camp on the Moon would allow the manual construction and maintenance of a new generation of space-based experiments: telescopes, particle accelerators, gravitational wave detectors, nurseries, power generation. and launch points for missions to the rest of the solar system.
As an added bonus, the risk of being hit by space objects (such as meteorites) is low, and the cable could be made to withstand small bumps, the researchers suggest.
The idea of a lunar space line is not new, but this latest study shows that it is now feasible in terms of cost and practicality. However, it is worth bearing in mind that this is only a proof of concept, and the work has yet to appear in a peer-reviewed journal. It has been uploaded to receive industry feedback on the arXiv.org server.
Be that as it may, it could give us a more viable alternative to low-cost space exploration than the classic space elevator, and at least the math has verified that.
We have calculated the tension in the space line, and we demonstrated that with modern materials it could be constructed within the fundamental limits of the materials, conclude the experts.
Is it an idea that seduces characters like Elon Musk?
Referencia: The Spaceline: a practical space elevator alternative achievable with current technology. Zephyr Penoyre, Emily Sandford. (Submitted on 25 Aug 2019) In preparation for submission to Acta Astronautica. arXiv:1908.09339
