by Jeff Foust
The High Frontier: An Easier Way
by Tom Marotta and Al Globus
Amazon Digital Services, 2018
ebook, 204 pp., illus.
In space, as in other fields, ideas come and go, returning after past failures in the hopes that changes in technology, policy, or economics will allow people to accept a concept they previously rejected. That appears to be the case with space settlements. In the 1970s, “space colonies” were all the rage among space enthusiasts, attracted by the idea proposed by Princeton professor Gerard K. O’Neill that giant habitats, many kilometers in size, would be the best place for humanity to live in space. There were NASA-sponsored studies of space colonies with lavish illustrations of the concepts, and ideas to use such facilities to enable space-based solar power (another idea that comes and goes) and other space industries. But, within a few years the concept faded away, with NASA ending its support and predictions that the Space Shuttle would enable frequent low-cost access to space failing to come true.
In the last few years, though, there’s been a push to bring back the idea, now often called “free space settlements” (avoiding the negative perception many have of “colonies.”) A new book by two space settlement advocates, Tom Marotta and Al Globus, offers an update of sorts of the original space colony concept O’Neill offered decades ago in his book The High Frontier, arguing that such settlements need not be as large and as expensive as O’Neill once thought.
As its subtitle suggests, the authors of The High Frontier: An Easier Way make the case that several changes in the original assumptions that drove the 1970s-era space colony concepts make such settlements more feasible today. One eschews the plan to place settlements at the Earth-Moon L-5 Lagrange point in favor of an equatorial low Earth orbit (ELEO) over the Equator at an altitude of 500 to 600 kilometers. That orbit gives such a facility radiation protection from the Earth’s magnetic field while also avoiding the South Atlantic Anomaly, a major source of charged particles. Doing so, they conclude, drastically reduces the mass needed for radiation protection: from five to ten tons per square meter of the facility’s surface to as little as 10 kilograms.
A second design change is to speed up the rotation rate of the facility needed to produce Earth-equivalent gravity. Previous studies assumed humans could tolerate rotation rates of no more than 1–2 revolutions per minute (RPM), but research suggests people can tolerate speeds of 4 RPM without any long-term consequences. That reduces the diameter of the facility, and hence its mass and cost.
Those changes, coupled with work to reduce launch costs, makes a settlement more feasible—or, at least, less infeasible. An initial concept mentioned in the book, called Kalpana, would be 112 meters in diameter and 112 meters long, weighing about 16,800 metric tons: enough to be carried by a little more than 100 flights of SpaceX’s Big Falcon Rocket (BFR) vehicle, at least according to designs the company disclosed last year. It’s still an expensive proposition, but one not as outlandish as the concepts from the 1970s.
While the authors do a good job exploring this alternative approach to space settlements, they’re less convincing about why such settlements should be built. They offer several potential applications for a facility, from tourism to manufacturing to even “telecommuting,” with people living in space but doing work on Earth. But telecommuting is more likely to work in the opposite direction—people living on Earth doing work in space through telerobotics—undermining the other business cases for a space settlement.
Later in the book the authors lay out a 12-step approach to space settlement development, starting with the introduction of vehicles like the BFR and concluding with the establishment of deep space settlements harnessing resources in asteroids. But that process relies on bootstrapping the creation of space settlement through tourism, starting with commercial modules on the International Space Station and growing to hotels capable of hosting up to 1,000 people in orbit. Given the disappointing pace of space tourism development in the last couple of decades, we may be waiting a long time for this.
That list also contains contradictions. That first step, low-cost reusable launch vehicles, would be intended to support markets like space solar power. But a later step envisions using the first settlements to “develop a solar power satellite assembly, checkout, test and deployment industry.” But if those facilities are already created—presumably using robotic assembly techniques—then the need for a space settlement to support them seems diminished. It’s the space advocates’ chicken-and-egg dilemma: which comes first, the solar power satellites or the space settlements? Maybe neither.
It’s interesting that the authors pin much of their hopes on the future of their idea on Elon Musk, calling his company’s BFR “almost the ideal craft” for enabling space settlements in ELEO. Musk, though, doesn’t seem that interested in space settlements in orbit, focusing instead on his driving ambition to make humanity multiplanetary through the settlement of Mars. There’s less mention in the book of Jeff Bezos, the far wealthier founder of Blue Origin. He seems far more enamored of space settlements, having been inspired by O’Neill’s work when he was growing up. If anyone can make space settlements happen, it’s Bezos, with his long-term vision and financial resources. Or, rather, if he can’t do it, perhaps no one can.