This is a story about Jeff Bezos, Elon Musk, and their epic head-to-head battle. It's the kind of thing that inspired my related, free e-books: Jeff Bezos Regrets Nothing and Elon Musk Has Very Big Plans

On late Friday afternoon, as Musk and Bezos waited, the tea leaves were read, the verdict was rendered, and the winner was declared.

It will be Musk's SpaceX, not Bezos's Blue Origin, that will take astronauts back to the surface of the moon for the first time since 1972, after SpaceX won a $2.89 billion NASA contract, beating out Bezos's company and others.

Musk celebrated, as Musk would, with a tweet: "NASA Rules!" adorned with rocket, heart, and star emojis.

Bezos, as far as I could find when I wrote this, has yet to respond -- even after he released his widely praised 6,500-word Amazon shareholder letter yesterday.

Musk and Bezos have been in one rumble after another over the years, waged largely on social media -- and it's developed beyond simply a competition between their companies to become "a full-blown rivalry," in the words of Christian Davenport, a Washington Post reporter and the author of The Space Barons.

Even as Tesla rides high, and as Bezos prepares to step down from the helm of the gargantuan company he started more than 25 years ago, there's something about building the moon lander, and what that might mean for the future of both companies and both men -- to say nothing of humanity itself -- that seems bigger and bolder.

This is despite the fact that the size of the NASA contract is tiny compared to each man's net worth. They've each gained and lost multiples of that amount, on paper, in a single day -- many times.

Musk, who started SpaceX in 2002 when he was 29, was driven in part to explore space by the realization that rocket technology hadn't really advanced very much in nearly 40 years.

"To a self-made Silicon Valley tech entrepreneur, this was stunning," Davenport writes in his book. "His company's mantra was: Set audacious, nearly impossible goals and don't get dissuaded."

Bezos, roughly seven years older, says he was first inspired by the memory of watching the Apollo 11 moon landing in 1969, when he was just 5.

He later nurtured his passion with a love of science fiction that led him to question the future of the human race, and what was truly possible in space.

Their private space rivalry goes back years, perhaps punctuated by the moment in 2013 when Musk outbid Bezos to acquire NASA's Launch Pad 39A, from which Apollo 11 and the Space Shuttle had been launched.

Bezos responded, as Davenport recounts, by buying Launch Complex 36, which was the spot from which NASA's unmanned missions to Mars and Venus had been launched. Davenport also talks about a meeting between Bezos and Musk to discuss their rocket ambitions in 2004 that didn't go well.

For all their accomplishments, I think it's fair to suggest that both Bezos and Musk view their space ventures as the true keys to their legacies far in the future, and the biggest contributions they'll make to world history.

That's why Bezos has said he intends to continue investing $1 billion per year in Blue Origin by liquidating his Amazon stock. And all of Musk's companies, according to Tim Fernholz's book Rocket Billionaires, are "explicitly intended to further human civilization."

Perhaps because they share this common purpose, there's a degree to which the rivalry sometimes seems more like a friendly, almost big brother/little brother competition than a blood feud.

I'm reminded of how Bezos congratulated Musk and SpaceX after a test of its high-altitude Starship rocket, which ultimately exploded. 

"Anybody who knows how hard this stuff is is impressed by today's Starship test," Bezos posted on Instagram. "Big congrats to the whole @SpaceX team. I'm confident they'll be back at it soon."

Still, there's no denying that the return to the moon later this decade, potentially as soon as 2024, is the near-term space prize that is most likely to inspire humanity again, and act as an even bigger launchpad for the people, technology, and companies involved.

The private space race might have just begun. But in this early, important, high-profile contest, they went head to head, and Musk is clearly the winner. 

(Don't forget to download the free e-books: Jeff Bezos Regrets Nothing, and Elon Musk Has Very Big Plans.)