{"id":543862,"date":"2022-12-08T12:00:18","date_gmt":"2022-12-08T17:00:18","guid":{"rendered":"https:\/\/www.rochester.edu\/newscenter\/?p=543862"},"modified":"2023-06-29T14:26:13","modified_gmt":"2023-06-29T18:26:13","slug":"cities-on-asteroids-it-could-work-in-theory-543862","status":"publish","type":"post","link":"https:\/\/www.rochester.edu\/newscenter\/cities-on-asteroids-it-could-work-in-theory-543862\/","title":{"rendered":"Cities on asteroids? It could work\u2014in theory"},"content":{"rendered":"

Rochester scientists use physics and engineering principles to show how asteroids could be future viable space habitats.<\/h2>\n

This past year, Jeff Bezos launched himself into space, while Elon Musk funded a space flight for a non-astronaut crew. Space collaborations between government and private entities, including Musk\u2019s SpaceX and Bezos\u2019s Blue Origin have become increasingly common. But with the recent emergence of the so-called \u201cNew Space\u201d movement, aerospace companies are working to develop low-cost access to space for everyone, not only billionaires.<\/p>\n

For a future beyond Earth, however, humans need places to accommodate homes, buildings, and other structures for millions of people to live and work.<\/p>\n

Right now space cities exist only in science fiction. But are space cities feasible in reality? And, if so, how?<\/p>\n

According to new research from University of Rochester<\/a> scientists, our future may lie in asteroids.<\/p>\n

In what they deem a \u201cwildly theoretical\u201d paper<\/a> published in the journal Frontiers in Astronomy and Space Sciences<\/em>, the researchers, including Adam Frank<\/a>, the Helen F. and Fred H. Gowen Professor of Physics and Astronomy, and Peter Miklav\u010di\u010d, a PhD candidate in mechanical engineering and the paper\u2019s first author, outline a plan for creating large cities on asteroids.<\/p>\n

\u201cOur paper lives on the edge of science and science fiction,\u201d Frank says. \u201cWe\u2019re taking a science fiction idea that has been very popular recently\u2014in TV shows like Amazon\u2019s The Expanse<\/em>\u2014and offering a new path for using an asteroid to build a city in space.\u201d<\/p>\n

A spinning space metropolis<\/strong><\/h3>\n

In 1972 NASA commissioned physicist Gerard O\u2019Neill to design a space habitat that could feasibly allow humans to live in space. O\u2019Neill and his colleagues worked out a plan for \u201cO\u2019Neill cylinders,\u201d spinning space metropolises consisting of two cylinders rotating in opposite directions, with a rod connecting the cylinders at each end. The cylinders would rotate fast enough to provide artificial gravity on their inner surface but slow enough that people living in them would not experience motion sickness.<\/p>\n

Since then, TV shows and movies including Star Trek<\/em> and books such as Orson Scott Card\u2019s 1985 novel Ender\u2019s Game<\/em> have depicted O\u2019Neill cylinder-like habitats populated with human beings. Both Bezos and Musk have referenced O\u2019Neill cylinders in their visions for future space habitats.<\/p>\n

However, while O\u2019Neill cylinders offer a solution to space\u2019s lack of gravity, getting the necessary building supplies from Earth to space to create the O\u2019Neill cylinders would be difficult and cost prohibitive.<\/p>\n

A pandemic project<\/strong><\/h3>\n

During the COVID-19 pandemic and lockdown, Miklav\u010di\u010d, Frank, and several Rochester students and colleagues\u2014John Siu \u201920; Esteban Wright \u201922 (PhD); Alex Debrecht \u201921 (PhD); Hesam Askari<\/a>, an assistant professor of mechanical engineering; and Alice Quillen<\/a>, a professor of physics and astronomy\u2014considered this conundrum of creating cost-effective O\u2019Neill cylinders.<\/p>\n

\u201c<\/span>All those flying mountains whirling around the sun might provide a faster, cheaper, and more effective path to space cities.\u201d<\/div>\n

\u201cThis project started as just a way for physicists and engineers to blow off steam, set aside worldly stresses for a while, and imagine something crazy,\u201d Miklav\u010di\u010d says.<\/p>\n

They soon discovered, however, that they might be onto something: could asteroids be used to create O\u2019Neill cylinders?<\/p>\n

A fast, cheap, and effective path<\/strong><\/h3>\n

Asteroids are rocky bodies orbiting the sun, leftover from the formation of the solar system approximately 4.6 billion years ago. Scientists estimate there are about 1,000 asteroids larger than one mile across traveling in our solar system.<\/p>\n

\u201cAll those flying mountains whirling around the sun might provide a faster, cheaper, and more effective path to space cities,\u201d Frank says.<\/p>\n

Besides their abundance in the solar system, asteroids have many other advantages for human habitation, including their rock layers, which provide a natural shield against deadly cosmic radiation from the sun.<\/p>\n

But asteroids have several major drawbacks, the researchers found: the rock that comprises asteroids is not strong enough to handle getting even one-third of Earth\u2019s gravity from spinning. Once an asteroid was set into rotation, it would merely fracture and break. Moreover, most asteroids are not even solid rock but \u201crubble piles\u201d\u2014clusters of loose boulders, stones, and sand held together by the weak mutual gravity of space. If the researchers wanted to make space habitats out of these asteroids, they\u2019d have to figure out how to work with rubble piles.<\/p>\n

Managing rubble<\/strong><\/h3>\n

Miklav\u010di\u010d\u2019s research focuses on granular systems\u2014systems composed of many tiny particles, such as sand or grain. In particular, he studies how these systems respond in environments with low or no gravity; for instance, how space rovers might impact and disperse granular surfaces of planets when they touch down.<\/p>\n

\u201cMy typical research and this project are on two ends of a spectrum,\u201d Miklav\u010di\u010d says. \u201cI\u2019m normally interested in the grain-level response of granular media, whereas this project was more of a big picture exercise managing rubble as a large system.\u201d<\/p>\n

Miklav\u010di\u010d and his colleagues conducted calculations of forces, materials, and strategies for constructing rotating asteroid settlements and came up with an idea for containing the rubble that would inevitably result from forming an O\u2019Neill cylinder out of an asteroid.<\/p>\n

Containing an asteroid<\/strong><\/h3>\n

Their solution? A very big, very flexible bag.<\/p>\n

The researchers imagine covering an asteroid in a flexible, mesh bag made of ultralight and high-strength carbon nanofibers\u2014tubes made of carbon, each just a few atoms in diameter. The bag would envelope and support the entire spinning mass of the asteroid\u2019s rubble and the habitat within, while also supporting its own weight as it spins.<\/p>\n

\u201cA cylindrical containment bag constructed from carbon nanotubes would be extremely light relative to the mass of the asteroid rubble and the habitat, yet strong enough to hold everything together,\u201d Miklav\u010di\u010d says. \u201cEven better, carbon nanotubes are being developed today, with much interest in scaling up their production for use in larger-scale applications.\u201d<\/p>\n

The process could theoretically go something like this:<\/p>\n