Back in the 1960s and ’70s, it seemed everyone was talking about orbital colonies and emigrating into space with their families. The publication of Gerard K. O’Neill’s “The High Frontier,” especially, came at a time of great enthusiasm about the possibility of mass migration beyond the Earth. So, what happened to those dreams of millions of us moving away from our home planet to live in orbit or elsewhere in the Solar System?
The idea of space colonization has a long history, stretching back to the 19th century when writers like Edward Hale, Jules Verne, and Kurd Lasswitz saw humans spreading out into space just as easily as they’d moved from continent to continent on Earth. In the 1920s, Irish physicist J. D. Bernal became one of the first scientists to describe orbital colonies in detail. As the material and energy needs of the human race grew, Bernal concluded, it would become natural someday to build habitats out in space to harness the Sun’s energy and provide extra living space. He conceived of self-sufficient globes, 10 miles across, that would each be home to 20,000 or 30,000 inhabitants.
Almost half a century later, Princeton physicist Gerard O’Neill based the scheme for his Island One colony on a small version of the Bernal sphere, some 500 meters in diameter. Rotating twice a minute this would generate an Earth-normal artificial gravity at its equator. O’Neill went on to design much larger orbiting colonies, including his Island Three concept which consisted of two immense rotating cylinders, anywhere from five to 20 miles long. Each cylinder would have six equal-area stripes running the full length of the colony, including three transparent windows and three habitable “land” surfaces. An outer agricultural ring would supply all the colony’s food needs. Materials to build Island Three would be launched into space from the Moon using a magnetic mass driver.
The location chosen for Island Three was L5—the fifth Lagrangian point—in the Earth-Moon system. L5 is a point of stable equilibrium in the Moon’s orbit, forming an equilateral triangle with the Earth and the Moon. No effort would be needed to keep the colony in place because the gravitational forces acting on it would always nudge it back into place.
Crucial to the success of such a habitat would be solar power satellites (SPSs), which could also be built from lunar materials. Unhindered by the Earth’s atmosphere, an SPS would collect solar energy non-stop, 24 hours a day, and at a much higher rate than any facility on the ground. Then it would transmit the energy it had gathered to where it was needed as a beam of microwaves. Between 1977 and 1980, the U.S. Department of Energy spent $25 million on research into SPSs and, for a while, it seemed that space colonies might become a reality within a generation or so. But in 1981, in the midst of a world energy crisis, the Carter administration axed the $5.5 million for SPS that had been in the budget for that fiscal year, and it was never restored. With the loss of the SPS program the dream of realizing an L5 colony any time in the foreseeable future effectively died.
Today we talk about returning to the Moon to build a base there, or to colonize Mars. But the emphasis has changed. The colonization of space, if it happens, is seen less as a grand-scale effort by national space agencies and more as an incremental affair building on the successes of private and commercial ventures. And perhaps, in the end, that’s how it should be.
Want to keep up-to-date with all things space? Be sure to “Like” AmericaSpace on Facebook and follow us on Twitter: @AmericaSpace