The Long Space Age: The Economic Origins of Space Exploration from Colonial America to the Cold War, by Alexander MacDonald, Yale University Press, 272 pages, $35

Sixty years ago, the Soviets launched Sputnik and, with it, the space race. For Americans who grew up since then, the exploration of space has always been linked closely with the government. Private space companies such as SpaceX and Blue Origin may have had successes, but they still arouse skepticism from people who cannot imagine anyone other than NASA or its foreign rivals sending people to the cosmos. But in The Long Space Age, the NASA historian and economist Alexander MacDonald uncovers a rich, multi-century history of privately funded space exploration. In the long view, the age of government-funded space travel may be a just a temporary detour from an older tradition.

In the beginning, the exploration of space took place from here on Earth, with the astronomical observatories of the late 18th through mid-20th centuries. These were funded by subscriptions from local community boosters, by donations from wealthy patrons, and only occasionally by the government. The resources devoted to these projects were equivalent to those of many modern space missions, often as much as a billion current dollars. The feds did fund some successful projects, such as the Naval Observatory and the Smithsonian. But there were also many failures, including a national astronomical observatory proposed by President John Quincy Adams, an amateur astronomer, who warned of the dangers of falling behind the Russians' large telescope. (Think of that as the first space race.) Congress batted down the idea, with members arguing that this was not a federal responsibility.

Space rockets, similarly, were at first a mostly private enterprise. MacDonald recovers the largely forgotten history of Robert Goddard, the American inventor of the liquid rocket, whose work was funded by the Guggenheim Foundation and others. Similarly, the Jet Propulsion Laboratory, later absorbed by NASA, started as a student rocket project in the 1930s in an arroyo near the California Institute of Technology. Not until the 1940s was most rocket science conducted on the government's dime.

Why did private funders pay for telescopes and rockets? Often, it wasn't about the science so much as the signaling. For example, Charles Yerkes—notorious for monopolizing streetcars in Chicago by means both fair and foul—helped finance the Yerkes Observatory in Wisconsin to signal his fundamental beneficence and to rehabilitate himself in the public eye. Any revised perception of Yerkes' character didn't last long, but the facility itself did, and a great many discoveries were later made there.

This motive hasn't disappeared in the age of NASA. The Apollo missions signaled that our space technology was superior to that of the Soviets, a goal that remains a driving force behind publicly funded human spaceflight. For many in Washington it doesn't matter much whether we have actual space accomplishments, as long as we maintain the appearance that we are on our way to achieving things in space.

For philanthropists and subscribers to private telescopes, the aim was to signal that their town or college was ahead of its competitors in science and technology. The science itself often took a back seat: It was always easier to raise money to build a monumental observatory with a donor's name on it than to endow astronomers to actually use it for new discoveries. And the subscription model frustrated the scientists, who had to give up observation time to the subscribers who had paid money for the privilege of looking at planets through telescopes. The modern equivalent of that comes when planetary scientists have to divert mission resources—power, mass, bandwidth, money—from scientific instruments to cameras on space probes, so the taxpaying public can view gorgeous pictures.

The last great private telescope was the 200-inch reflector that first saw starlight in 1948 on Palomar Mountain in San Diego County. It was funded by the Carnegie and Rockefeller foundations, managed by Caltech, and named after the entrepreneurial astronomer George Ellery Hale. It went into service just as the Cold War was heating up and right after the Manhattan Project showed the way to big-government science by yielding the world's first nuclear weapons. Soon we were in the era of missile and spy-satellite programs, of the Apollo missions, of government space probes, of the Space Shuttle and the International Space Station—the familiar federal space program that has accomplished much but disappointed many who dream of how much more we could be doing for the money.

But a funny thing happened in the 1990s. Some of the orphans of Apollo, people disappointed by the stillborn age of space travel, temporarily put aside their childhood dreams of lunar bases and instead made money on the internet. A decade and a half ago, Elon Musk and Jeff Bezos took some of their winnings from PayPal and Amazon, respectively, and started SpaceX and Blue Origin. David Masten cashed out his Cisco shares to found Masten Space Systems, which has pushed forward the crucial technology of vertical rocket landing. Game developer John Carmack (initially most famous for Doom) did something similar with Armadillo Aerospace. Paul Allen, a Microsoft founder who had funded Burt Rutan's winning suborbital XPRIZE entry, started a launch company of his own.

All these efforts have had their teething problems, but both SpaceX and Blue Origin have proven their space vehicles are reusable (though only suborbitally in the latter case, with plans for orbit in the next few years). SpaceX's Falcon 9 is already the lowest-price ride, and the competition between the two (and perhaps others, such as United Launch Alliance) combined with their reusability will continue to drive down the high launch costs that have long held back all but governments and the owners of high-revenue payloads such as communications satellites from engaging in space activities.

At the same time, Moore's Law—the observation that the number of transistors in an integrated circuit tends to double roughly every two years—is finally starting to affect satellite costs as well. They are now being miniaturized (as "cubesats"), and their capability is increasing to the point that they will soon be manufactured and launched in large quantities, at low cost, with rapid development cycles. For instance, Planet Labs is replacing their dozens of Earth-observing birds, essentially smartphones in orbit, with new versions every few months. And there are at least two funded proposals (one by SpaceX) to provide global low-latency internet using dozens or hundreds of medium-orbit satellites.

What does this mean for the future of space exploration? Every 10 years, NASA does a "decadal" survey describing the most important targets in space and planetary science. The sexiest mission right now is the search for extraterrestrial life, particularly in the ocean moons of Europa (orbiting Jupiter) and Enceladus (circling Saturn). Both spout geysers whose plumes may contain biological traces. Rep. John Culberson (R–Texas), chairman of the subcommittee that would fund a NASA mission, has a particular interest in Europa.

But with reduced launch and space hardware costs, perhaps using cubesat technology, it may soon be possible to do the Enceladus mission for a few hundred million dollars, and perhaps just a couple of hundred—at least for a fast flyby to taste the geysers and whet the appetite for further investigation. This is an amount well within the capability of many billionaires and foundations.

Former NASA astrophysics director Jon Morse has started a foundation specifically for such purposes; it's called the BoldlyGo Institute, and he is seeking philanthropists for it. The Russian billionaire Yuri Milner is funding a miniature laser-propelled starship project to look for life in nearby solar systems. Elon Musk, whose declared ambition is to die on Mars ("but not necessarily at the point of contact") is funding a private mission of perhaps two "Red" Dragon capsules to that planet in 2020, and NASA will send some instruments along for the ride. Jeff Bezos recently sold $1 billion worth of Amazon stock for the express purpose of his annual investment in Blue Origin.

MacDonald's book puts this coming private space age in a historical context. Seven decades after the Cold War launched the era of big-government space science, we're finally returning to the longer American tradition of privately funded space research.

CORRECTION: The original version of this story stated that Sputnik launched 70 years ago, not 60.