A few years ago, a Silicon Valley billionaire decried that he and his friends dreamed of flying cars, and instead got 140 characters. He was wrong: They, along with entrepreneurs and governments around the world, got much more — a space race on steroids.

The big picture: From Dubai to the U.S., Tokyo to Moscow, Tel Aviv to Beijing and more, billionaires, privateers and political leaders are vying to land on the Moon, colonize Mars, mine asteroids — and just get off the Earth. "Whatever we have evolved into hundreds and thousands of years from now, we'll look at these decades as when the human race moved off the planet," said Peter Diamandis, chairman of the X-Prize Foundation.

There are a handful of catalysts to the race, including national pride and irresistible interest in an estimated future multi-trillion-dollar industry. But neither of those has primarily driven the private commercial actors who are the most powerful forces behind the new age — billionaires like Jeff Bezos with his Blue Origin, Elon Musk with SpaceX, and Richard Branson with Virgin Galactic.

For them, the primary motivation appears to be romantic. All grew up amid the Apollo program and "Star Trek," and viewed the stars as, in Jim Kirk's words, "the final frontier," a place where humans were at long last going, Diamandis tells Axios. They thought they possibly could even go up, should science develop rapidly, and were deeply disappointed when, in the 1970s, NASA stopped sending humans to deep space.

"But then they made enough money to do it on their own."

— Peter Diamandis

Diamandis himself helped ignite the race with a $10 million prize competition, launched in 1996, for the first private actor to send a rocket into suborbital space. When it was awarded in 2004, the private industry took off.

Between the lines: A space program has become a must-have for governments, and not just for the usual players:

United Arab Emirates: In 2021, coinciding with the country's 50th birthday, the UAE plans to have a spacecraft orbiting Mars.

In 2021, coinciding with the country's 50th birthday, the UAE plans to have a spacecraft orbiting Mars. Saudi Arabia is investing $1 billion in Branson's space companies.

is investing $1 billion in Branson's space companies. Last month, Indian Prime Minister Narendra Modi said he aims to put humans in space within four years.

Narendra Modi said he aims to put humans in space within four years. Israel's commercial SpaceIL plans to land a spacecraft on the Moon next year.

All this activity looks a lot like the centuries-ago Age of Exploration, says astrophysicist Neil deGrasse Tyson, who tells Axios that we are now becoming "spacefaring nations."

The result can be peaceful enterprise, Tyson says. As long as people are just going places, "then do what the hell you want in space. Go mine asteroids, set up colonies. It's a big universe."

But, he goes on, "if you go to the Moon or to Mars and set up a military base, that can be viewed as a threat."

To protect American interests, President Trump last summer ordered the establishment of a Space Force.

Already, says Nicholas Wright, a U.K.-based analyst, equipment in orbit jams signals, blinds with lasers, and spies using cyber tools. That makes him wonder, "Is space fundamentally a military story?"

It won't be, if the private players have anything to do with it. By 2040, estimates Morgan Stanley, the space economy will be worth $1.1 trillion; Bank of America estimates $2.7 trillion.

As of now, these numbers are notional; the private sector is still trying to decipher what it can do in space that it cannot on Earth — or that millions of people will pay for.

Says Diamandis, "I am focused on, 'Can you build a business that makes money in space?'"

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Editor's note: This deep dive was first published in October of 2018.