Week 9, Space + Art

Artistic Vision of a Space Elevator (Dvorsky)

The idea of a space elevator is a truly fascinating idea, of which I spent many hours

Physical Diagram from Wikipedia

pondering the feasibility. The basic idea is that there would be a “counterweight” or huge mass (like an asteroid) in space (twice the circumference of the earth in distance from the surface), attached to earth by an ultra-strong cable so that it would spin in line with the earth (same angular velocity), and there would be enough tension in the cable so that an elevator could climb up it like a rope (Aravind, 2007). Think of a balloon tied to the ground and an ant climbing up it, the balloon being the counterweight, and the ant being elevator and cargo. The buoyant force of the balloon is analogous to the centrifugal force experienced by the counterweight, which comes from an object being spun in circles and wanting to fly outwards (think of swinging a ball on a rope in circles and then letting it go). The impact of a space elevator would be unimaginable, as space travel would be much less costly and dangerous.

The issues in construction and maintenance of such an evaluator are numerous and not fully understood. The biggest issue and reason why it has been truly impossible for more than 100 years since the idea's conception is that there is no cable material strong enough to withstand the tension of supporting the counterweight, cable, and cargo/elevator system (and light enough to not compress itself) (Fleming, 2015). The reason for the interest in the idea of the elevator recently, has been the development of carbon nanotubes, which some believe could be strong and light enough to support the tension of the elevator system (Fleming, 2015). There are also similar structures being developed out of Penn State called diamond nanothreads that some believe could be strong enough as well (Kennedy). Both these materials can only be made in small amounts (~1m) and thus we are still many years from the possibility of a realistic cable (Fleming, 2015).

Other practical issues of serious concern, summarized well by Dvorsky, are waves and vibrations in the cable causing violent effects (possibly exaggerated in the video above), small perturbations from vertical causing feedbacks and divergent motion, huge shearing effects from wind and storms, grounding the entire atmosphere, impacts from debris and aircraft, terrorist attacks, and then of coarse the enormous cost and effort needed to construct and maintain a structure more than twice the circumference of the earth (never been done for any object). I also pondered the idea of whether it would pull the earth out of orbit slightly, but was unable to confirm or deny that with much certainty.

Given all these issues and concerns I would say that it is unlikely that we could ever build, maintain, and protect such an ambitious project, but I would love to be proven wrong.

Works Cited

Aravind, P. K. "The physics of the space elevator." American Journal of Physics 75.2 (2007): 125-130.

Dvorsky, George. "Why We'll Probably Never Build a Space Elevator." Io9. N.p., n.d. Web. 01 June 2015.

"File:Space Elevator Structural Diagram--corrected for Scale+CM+etc--regenerated as SVG.svg." Wikipedia. Wikimedia Foundation, n.d. Web. 01 June 2015.

Fleming, Nic. "Should We Give up on the Dream of Space Elevators?" BBC. BBC, 19 Feb. 2015. Web. 01 June 2015.

Kennedy, Barbara K. "Smallest Possible Diamonds Form Ultra-thin Nanothreads." — Eberly College of Science. Penn State, 21 Sept. 2014. Web