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Full Version: Using biological design in engineering an elevator to space
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https://singularityhub.com/2018/08/26/wh...ter-space/

EXCERPT: . . . In recent years, engineers have been able to build on grander scales thanks to the strength and reliability of substances such as novel steel alloys. But as we enter the realm of megastructures—those of 1,000 km or more in dimension—maintaining safety and structural integrity has become a fiendish challenge. That’s because the bigger something becomes, the more stress it experiences due to its weight and size [...] It turns out that biological design, equipped with around 3.8 billion years of experience, might help solve this puzzle.

[...] bones nor tendons in our bodies [...are...] often compressed and stretched well beyond the point at which their underlying substances might be expected to break. Yet these components of human bodies are still much more ‘reliable’ than their sheer material strength would suggest. [...]

How does biology handle these loads? The answer is that our bodies constantly repair and recycle their materials. In tendons, collagen fibers are replaced in such a way that, while some are damaged, the overall tendon is safe. This constant self-repair is efficient and inexpensive, and can change based on the load. Indeed, all structures and cells in our bodies are in constant turnover; it’s estimated that almost 98 percent of the atoms in the human body are replaced every year.

We recently applied this self-repair paradigm to see whether it’s possible to build a reliable space elevator with available materials. A common proposed design features a 91,000 km-long cable (called a tether), extending out from the equator and balanced by a counterweight in space. The tether would consist of bundles of parallel fibers, similar to collagen fibers in tendons or osteons in bones, but made from Kevlar, a material found in bullet-proof and knife-proof vests.

Using sensors and artificially intelligent software, it would be possible to model the whole tether mathematically so as to predict when, where and how the fibers would break. And when they did, speedy robotic climbers patrolling up and down the tether would replace them, adjusting the rate of maintenance and repair as needed—mimicking the sensitivity of biological processes. Despite operating at very high stress compared to what materials can sustain, we showed this structure would be reliable and would not demand exorbitant rates of replacement. Moreover, the maximum strength the material would need to possess to achieve a dependable structure was cut by an impressive 44 percent....

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