The stairway to the heavens starts in Texas. In 2003, a young Elon Musk was scouting for a suitable location to fulfil his dream of becoming a space pioneer.

A year earlier, he had started Space Exploration Technologies Corp – SpaceX for short – with the aim of building rockets and one day sending humans to the moon, or even Mars.

First, though, he had to find somewhere to carry out the noisy and dangerous job of rocket testing. The wide open spaces of freewheeling Texas, where folk are more relaxed about firearms and explosives, provided the perfect solution. There, amid the rattlesnakes and fire ants and searing heat, Musk set to work.

At the same time, 800km across the state, another American entrepreneur was looking for a place to indulge his own space-flight ambitions.

Jeff Bezos had set up his space company, Blue Origin, two years before Musk’s, but he had been sidetracked by problems at Amazon, his internet shopping business that came close to bankruptcy in 2002. When it rebounded a year later, Bezos was ready to reach for the stars. Away from prying eyes, near the tiny Texan town of Van Horn, he discovered the ideal spot for launches.

Unlike Musk, Bezos was shy about his plans, and when the helicopter taking him to visit potential sites crash-landed, it was as much a setback because of the publicity as for the damage. A shaken Bezos walked away from the wreck with only minor injuries, explaining that he was looking for a ranch. Few suspected when he bought thousands of empty acres in 2004 that he was more interested in rockets than rodeos.

So began the modern space race – not a battle between rival nations, or political doctrines. Not even a battle between competing technologies. Instead, a trial of strength between two science-fiction-obsessed billionaires who had bought everything money can buy on Earth and were now striving for infinity and beyond.

Musk, 49, controls Tesla, the world’s biggest car company by capital value. Raised in South Africa, he moved to the United States at the age of 19 and spent his early 20s sleeping on sofas and showering at the YMCA. He made a fortune from X.com, a financial services company that merged to form PayPal. He is now worth about US$148 billion, according to the Bloomberg Billionaires Index, making him the second richest person on the planet.

Bezos, 56, the wealthiest human being there has ever been, has a net worth of about US$183 billion. His first job was as a burger-flipper at McDonald’s. After graduating from Princeton University he worked on Wall Street before quitting to start Amazon in 1994.

From their humble beginnings in the Texan scrubland the two have risen to dominate the space industry. In May, Musk’s SpaceX made Robert Behnken and Douglas Hurley the first astro­nauts to fly from American soil since 2011. Last month, Musk’s Falcon 9 rocket successfully transported four more astronauts to the Inter­national Space Station – the first mission of its kind by a commercial operator.

Not to be outdone, Bezos aims to launch a rocket next year that will be bigger and mightier than the Falcon 9 and has already unveiled plans for a module designed to land astronauts on the moon for the first time since 1972.

Musk’s SpaceX and Bezos’ Blue Origin have outpaced even the likes of Boeing and Lockheed Martin, with their vast factories employing tens of thousands of people. Now the two are duking it out with each other, fuelled by money, ego and, appropriately, a fascination with television and cinema’s most popular sci-fi franchises: Star Trek and Star Wars.

Bezos launched a space capsule containing a dummy called Mannequin Skywalker to prepare for his own manned missions. In the next decade these men are set to reap the huge commercial rewards that space offers – by launching satellites for internet, telecoms and surveillance, and by transporting space tourists. Nasa has got out of the business of sending astronauts into low Earth orbit and started subcontracting to Musk and – soon – to Bezos, a business worth billions of dollars. You might think there would be room for both in space. But what started as a lighthearted spat has turned into an epic rivalry that may end only when one has zapped the other from orbit.

Lori Garver, a former Nasa executive who has had dealings with both men, says that despite their declarations about sending colonists to other planets to save the human race from disease or obliteration by war or asteroid, their motives may be less altruistic. “I love the ‘I want to advance humanity and save the species’ [idea],” she says, “but it’s [just as much] boys and their toys.”

Rewinding to before battle lines were drawn, there was a brief time when Bezos and Musk were space buddies. In 2003, they shared a dinner in San Francisco arranged by Tomas Svitek, a consultant who had worked for both men. Svitek knew they had similar interests and imagined they might even join forces. Afterwards he said each had spoken well of the other: “Cool meeting – the guy is fun, we enjoyed it.” Having sized each other up, they went their separate ways.

According to Christian Davenport, a reporter for The Washington Post and author of The Space Barons (2018), much later Musk recalled the meeting thus: “I did my best to give good advice, which he largely ignored. It was very clear technically he was barking up the wrong tree.”

The two men found themselves fishing from the same limited pool of specialists in rocketry. In 2008, after one of Musk’s engineers left to join Blue Origin, SpaceX called in lawyers, alleging the engineer had violated his contract and that Blue Origin had attempted to “recruit multiple SpaceX employees with specific and detailed knowledge of SpaceX’s design efforts”.

The lawsuit was dismissed but the fuse was lit. When SpaceX tried to get exclusive use of Nasa launch pad 39A in 2013, Blue Origin, which had submitted a rival bid, filed a formal protest with the government. US senators batting for Bezos warned Nasa that “blocking the use of the pad to all but one company would essen­tially give that company a monopoly”.

Musk hit back, describing it as a “phoney blocking tactic” and calling the protest a case of “launch site envy”. “Filing a lawsuit for 39A when they haven’t even got so much as a toothpick into orbit […] So it was absurd for [Bezos] to claim that Blue Origin should get 39A,” Musk fumed. He fired off an email to the SpaceNews website calling Bezos’ bluff: “If they do somehow show up in the next five years with a vehicle qualified to Nasa’s human rating standards […] we will gladly accommodate their needs.” The chances of that happening, concluded Musk, were about the same as discovering “unicorns dancing in the flame duct”.

SpaceX won the dispute and Musk’s employees celebrated by decorating the launch pad with 100 inflatable unicorns. According to Davenport, a picture of Captain Jean-Luc Picard from Star Trek adorned SpaceX’s offices, with a speech bubble saying: “What the f*** does Blue Origin need a Florida launch pad for?”

It was not long before Bezos and Musk locked horns again, over plans to use drone ships to provide safe landing platforms for reusable rockets. Bringing rockets back to Earth after a mission and then flying them back into space seemed an obvious way to cut the cost of space flight, but it was technically tricky. Unmanned ships offered a solution: if a rocket returning to land on a drone ship in the middle of the ocean strayed off course and crashed, no one would get hurt.

The problem was that Bezos laid claim to the idea and produced a patent as evidence he had thought of it first. Musk challenged the patent in court, claiming the idea was “something that’s been discussed for, like, half a century”, he later told Davenport.

Again, judges ruled in Musk’s favour. Bezos did not immediately respond to the setback, perhaps biding his time. Then, in late 2015, after Musk had landed the booster stage of his reusable Falcon 9 rocket for the first time, Bezos, who had achieved a similar feat the previous month, took to Twitter. Reminding Musk that he had made the breakthrough first, Bezos tweeted, with what seemed like a heavy note of sarcasm: “Congrats, SpaceX. Welcome to the club.”

If the remark was intended to rain on Musk’s parade, it hit its mark. “That was a pretty snarky thing for him to say,” Musk said, frustrated at the comparison between the two launches. While Bezos’ tiny craft could barely touch the edge of space, his more powerful rocket could reach orbit.

The rivalry turned to thinly disguised hostility the following year. Days before Musk was due to launch a US$195 million satellite into orbit, the rocket carrying it spectacularly exploded on the launch pad, destroying its payload and damaging the launch tower at vast expense. It turned out that the satellite was to have been used by Facebook to reach millions of new customers in Africa.

In a rare show of emotion Facebook’s Mark Zuckerberg vented his feelings, saying he was “deeply disappointed [at] SpaceX’s launch failure”. Musk was also upset – and angry. He tweeted that the fireball may have been no accident, and called the loss of the rocket “the most difficult and complex failure we have ever had in 14 years”. Hinting at sabotage, his tweet said that investigators were “particularly trying to understand the quieter bang sound a few seconds before the fireball goes off. May come from rocket or something else”.

Later, Musk explained to Davenport: “We literally thought someone had shot the rocket. We found things that looked like bullet holes and we calculated that someone with a high-powered rifle, if they had shot the rocket in the right location, that exact same thing would have happened.”

SpaceX staff reviewing the footage found “an odd shadow and then a white spot” on the roof of the neigh­bouring building. Two weeks after the explosion, a SpaceX employee arrived at the building asking if he could have access to the roof – from where there is a clear line of sight to Musk’s launch pad. He was turned away. US Air Force investigators were called in, but found nothing suspicious. Yet Musk still had doubts about the cause of the explosion.

Then, while SpaceX was still reeling from the shock of the launch pad disaster, Bezos delivered another blow, announcing he would build a rocket that would outstrip Musk’s Falcon in size. Named New Glenn, after John Glenn, the first American to orbit the Earth, it will be the world’s largest orbital rocket – the biggest since the Saturn V that carried men to the moon, unless it is beaten to lift-off by Nasa’s colossal Space Launch System (SLS). Inaugural flights for New Glenn and SLS are pencilled in for next year.

If proof were needed that the gloves were finally off, this was it. Not only did it demonstrate Bezos’ greater financial muscle, it was a clear statement of his aim to reach further into space than Musk. In the words of the world’s most famous split infinitive – he was determined to boldly go where no man has gone before.

If it seems unlikely that TV science fiction could have such a hold on a hard-headed multibillionaire, consider this: after years of pleading with the owners of the Star Trek franchise, Bezos was finally given a cameo role as a talking alien in Star Trek Beyond (2016).

“For years I have been begging Paramount to let me be in a Star Trek movie,” he admitted. “I was very persistent. I said, ‘Look, I’ll put any amount of make-up on. I’ll be invisible. Nobody will know it’s me. But I want a speaking part.” In a further tribute to his favourite show, Bezos named his dog Kamala after a Star Trek character (and before the name was widely associated with the Democrats’ vice-president-elect).

Musk made his own film appearance in Iron Man 2 (2010), as himself. The walk-on part was a thank-you from its director, Jon Favreau, for whom Musk was an inspiration for Tony Stark, the American businessman who morphs into Iron Man.

Musk is also a Star Trek fan and christened his yet-to-be-launched interplanetary space vehicle Starship – as in the USS Enterprise. He made arrangements to carry on one of his rockets the ashes of James Doohan, the actor who played Star Trek’s Scotty, so they could be scattered in space. Cruelly, but aptly, given that Scotty’s recurring duty was to warn Captain Kirk that the Enterprise would break apart if he pushed it too hard, the rocket exploded in mid-flight. Musk still earned the gratitude of Trekkies.

When I first interviewed Musk, in 2011, he had succeeded in putting a Falcon 1 rocket into orbit after three failed attempts. It was his single greatest achievement, he said. “It did take me four tries. I kinda had to learn it from scratch. I mean I do have a physics background, and that’s helpful.

“The reason I began looking at space [was] not from the perspective of starting a company, but trying to understand why we had not advanced further from the Apollo era. Other areas of technology have advanced considerably and yet we’ve gone backwards in that arena.

“If you’d told someone in 1969 that the United States wouldn’t even be able to get [humans] into orbit 42 years later they would have expressed disbelief – if not punched you. We really need to see an influx of the world’s best entrepreneurs and technologists into space flight to advance the technology and push the frontiers.”

Of course, just as the rewards are potentially huge, so is the risk. Musk himself has admitted that “the fastest way to make a small fortune in the aerospace industry is to start with a large one”. Billions have been lost by private rocketeers carried away with the romance of space exploration.

Musk admitted to me in a later interview that he came close to a nervous breakdown when he thought his SpaceX endeavour was about to fail, leaving him penniless. At the eleventh hour Nasa stepped in with a US$1.6 billion contract.

“Yeah, I think that was the darkest time. I remember waking up and thinking, ‘Wow, I never thought I was capable of a nervous breakdown.’ I thought that was for soft people or something, and I was, like, ‘Wow, this is the closest I’ve ever come.’ And fortunately, the next day, Nasa called. If [it] hadn’t, we would have gone bankrupt a few days after Christmas.”

Musk is prepared to talk candidly about his disasters and his supporters love him for his heroic failures and swashbuckling style. SpaceX shared on social media a blooper reel of mishaps showing Musk’s reusable Falcon rockets crashing into the sea instead of landing on drone ships as they were supposed to. Bezos has had disasters, too – there has never been a rocket development programme without them – but he doesn’t advertise the fact. Neither, as a rule, does he give interviews to the press. Our approaches were politely declined.

Bezos is steady and systematic. He has succeeded in launching and landing the same rocket six times to demonstrate its reusability, painting a tortoise on the side after each attempt. It symbolises Bezos’ philosophy, one that, in the hare and tortoise parable at least, eventually wins the race. “Step by step, ferociously” is Blue Origin’s motto, an approach explained by Bezos in an email to fans. “In the long run, deliberate and methodical wins the day, and you do things quickest by never skipping steps.”

Bezos knows this is a marathon not a sprint, and he is sitting on a mountain of money that could give him an unassailable lead. There’s an old saying in the space industry: “No bucks, no Buck Rogers.”

Bezos has said: “There’s a very real sense in which Amazon […] is a lottery winning for me. I’m taking those lottery winnings and investing them in Blue Origin.”

Revealing a rare nugget about Blue Origin’s finances, he added: “I sell about US$1 billion of [Amazon] stock a year and I use it to invest in Blue Origin.”

While Musk’s contract with Nasa gave him a head start, Bezos has been catching up. Like Musk, he has tapped into government agencies. When both men bid for funding to develop landing systems that would allow astronauts to descend to the surface of the moon or other planets, Bezos won the lion’s share.

In April, Nasa awarded him US$579 million; Musk’s contract was worth US$135 million. Bezos also received US$500 million from the US Space Force – a delightfully named arm of the US Air Force charged with countering threats in outer space – to help develop New Glenn, the rocket he hopes will give him an edge over his rival and stand as a symbol of Blue Origin’s superiority.

If you doubt that two such brilliant men could be involved in what amounts to point scoring, you only have to look at how their rockets have leapfrogged each other in size. When in 2016 Bezos announced a bigger rocket than Musk’s Falcon 9, his rival went one better by unveiling what he called an interplanetary transport system. Musk’s new rocket would stand 121 metres tall – 24 metres higher than New Glenn – and supposedly be capable of flying passengers to Mars by 2024.

It has since been rechristened Starship, and test flights of the booster stage have already begun. Bezos then revealed plans for his New Armstrong rocket, named after Neil Armstrong, the first man to walk on the moon. Its details are secret, but it is almost certainly a challenger to Starship, with similar capabilities or better.

The two men even went head to head over plastic spacemen. Coveting Bezos’ cleverly named Mannequin Skywalker, Musk put his own dummy on a rocket to intercept Mars’ orbit and, courtesy of David Bowie, named him Starman. Bezos couldn’t resist a sideswipe at his rival’s ambitions to colonise Mars. “My friends who want to move to Mars,” he announced at a lecture in New York. “I say, do me a favour – go [and] live on the top of Mount Everest for a year first and see if you like it, because it’s a garden paradise compared to Mars.”

Behind the antics of rich-man rivalry, however, there are also serious financial rewards up for grabs. The prize is not in mining rare metals from asteroids
, or establishing off-world colonies. Instead it’s a new age of the internet. For an online shop revenues could rocket.

Musk also realised the potential and has laid plans for a necklace of 12,000 satellites circling the globe and beaming high-speed internet to the billions without access. The potential of the project, called Starlink, is mind-boggling. The total cost to design, build and deploy the constellation was estimated by SpaceX in May 2018 to be about US$10 billion. But internal documents leaked in January 2017 indicated that SpaceX believes the satellite business could bring in revenues of US$30 billion.

Once again Bezos is hot on Musk’s heels. He has won permission to launch 3,236 satellites under a rival programme called Project Kuiper (pronounced Ki-per) that would reach the “tens of millions of people who lack basic access to broadband internet”. He might have added that this would conveniently give them access to his Amazon store and hugely boost the number of potential customers.

Running Kuiper Systems is a savvy executive called Rajeev Badyal, who understands the satellite business possibly better than anyone, and has an intimate knowledge of Musk’s Starlink constellation. That is because he was working for Musk and running Starlink before switching sides.

Whoever wins the race to be the first global internet supplier is likely to be hailed as a giant of technology, an inventor who will have changed the lives of human­kind. As Ashlee Vance, Musk’s biographer, put it: “Imagine you have a rocket company to send up these satellites and billions of dollars and a great many people take your ideas seriously. That’s not [just] intoxicating. It’s [having] liquid cocaine intravenously and making love to everything available on Mount Olympus over the course of a four-day bender.”

Musk and Bezos recently cooled the rhetoric, perhaps as a result of being distracted by more earthly matters. Both found their private lives under scrutiny. At the start of last year the American media discovered that Bezos was having an affair with Lauren Sánchez, a helicopter pilot who founded Black Ops Aviation, a company that filmed promotional videos for Blue Origin. Bezos immediately announced that he and his wife, MacKenzie, were divorcing.

Meanwhile Musk was named in the Johnny Depp libel trial after he dated Amber Heard, Depp’s wife, though Musk insisted their affair had happened since Depp and Heard’s divorce. Musk is currently in a relationship with Claire Boucher, a Canadian singer-songwriter known professionally as Grimes, with whom he has a young son, named X Æ A-Xii. Temporarily, at least, the feud has been put on hold.

Beyond the intoxication, the boys toys, the billionaire adventures and the vast commercial potential, some see other, even bigger considerations in the long run. There are huge strategic implications bound up in the two billionaires’ space dreams. So much so that you could argue that the corporate ingenuity of Bezos and Musk are America’s best hope of countering the rising commercial and military might of other space superpowers, notably China and Russia.

Could the billionaires one day join forces in the national interest? Don’t bank on it. In the freezing temperatures of space, revenge is a dish best served cold.