Elon Musk and Jeff Bezos are in an epic, years-long feud over space travel. Here's a timeline of the billionaires' most notable battles.

Jeff Bezos and Elon Musk, two tech moguls with grand visions for exploring and settling humans in space, have increasingly found themselves feuding over what our future in that final frontier should look like.

Their disagreements mainly arise because both are pursuing reusable rockets , next-generation spacecraft , and ambitious space-settling plans . In May, for instance, Bezos unveiled a moon lander design by his spaceflight company, Blue Origin; in that presentation, he criticized the idea of populating Mars the overarching goal of SpaceX, Musk's rocket company.

That dig was made live onstage, but other times quarrels between Musk and Bezos appear on world stages like Twitter.

Most of the sparring seems innocuous. However, some of the billionaires' battles with the space companies they founded have worked their way into courts and government agencies .

The relationship between Bezos and Musk wasn't always so tense, though.

"As time has gone on and these companies have been successful, ambitions have grown," Ashlee Vance, who wrote a biography of Musk, told The Guardian in 2016. "Musk and Bezos used to be cordial, but they're vicious now."

Here's a short timeline of how they got to this point.

Bezos founded Blue Origin in 2000 as Amazons success surged.

BusinessInsider USA Images

Charles Platiau/Reuters

Musk, meanwhile, used the money he earned from eBays purchase of PayPal to launch SpaceX in 2002.

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AP

In 2004, the two met for a friendly dinner and talked about rockets. Even then, though, there was an adversarial spirit. "I actually did my best to give good advice, which he largely ignored," Musk said of meeting Bezos.

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Shutterstock

Source: " The Space Barons "

For about a decade, as each company experimented with rocket designs on private land in Texas, the two men largely kept their criticisms of one another out of the public eye.

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SpaceX/YouTube

That changed in 2013, after NASA asked companies to submit pitches for how they might use Launch Complex 39A in Cape Canaveral, Florida. Apollo and space-shuttle missions once launched from that historic site, but NASA was no longer using it.

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Dave Mosher

SpaceX told NASA it wanted to use the pad exclusively. But then Blue Origin and United Launch Alliance a rival of SpaceX filed a joint protest with the government. Musk dubbed the move a "phony blocking tactic."

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Kyle Grillot/Reuters

Sources: Space News , NBC

SpaceX later said it was open to sharing the site with NASA and other private companies if necessary. By the end of 2013, NASA agreed to lease the launchpad to SpaceX.

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SpaceX/Flickr

Another bitter battle came less than a year later, this time over drone ships. Such boats are autonomous, flat-decked, and able to serve as landing pads for huge rocket boosters. The rocket segment can then be reused, saving millions of dollars.

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Blue Origin via YouTube

Blue Origin filed a patent for the concept in 2010, and it was granted in 2014. Musk wasnt happy, since drone ships are key to SpaceXs plans to reuse boosters. SpaceX didnt want to pay Bezos company to use a drone ship.

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USPTO

Source: Geekwire ( 1 , 2 )

SpaceX petitioned to invalidate Blue Origins patent, stating that "the rocket science claimed in the ... patent was, at best, old hat" by 2009. The judge ruled mostly in SpaceXs favor, and Blue Origin withdrew 13 of 15 claims in the patent.

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Getty / David Ryder

SpaceX had a point the concept was even featured in the 1959 Soviet sci-fi film "Nebo Zovyot," or "The Sky Beckons."

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Dovzhenko Film Studios

Sources: IMDB , YouTube

Not long after SpaceX claimed victory, Musk and Bezos began clashing in public. In November 2015, Blue Origin landed its first reusable rocket, called the New Shepard. "The rarest of beasts a used rocket," Bezos tweeted with a video.

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Blue Origin/YouTube

Source: Twitter

Musk couldnt help but chime in. "Not quite rarest. SpaceX Grasshopper rocket did 6 suborbital flights 3 years ago & is still around," he tweeted in response to Bezos.

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Screengrab from spacexchannel on YouTube

Source: Twitter

Musk went even further with his one-up. He added that it takes 100 times more energy to launch something to geostationary orbit (about 22,236 miles up) which is what SpaceXs Falcon 9 rocket does than to suborbital space (about 62 miles high), where Blue Origins New Shepard goes.

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AP Photo/Jae C. Hong

Source: Twitter

In December 2015, SpaceX successfully landed its first orbital-class rocket booster on a drone ship. Bezos praised the company in a tweet...

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SpaceX via Flickr

... But with a side of shade. Referencing Blue Origins accomplishments with landing New Shepard, Bezos said: "Congrats @SpaceX on landing Falcons suborbital booster stage. Welcome to the club!"

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Cliff Owen/AP

Source: Twitter

The two billionaires also occasionally drop snide remarks about one another during press interviews. A few weeks after SpaceXs rocket-booster landing, for instance, the BBCs Rory Cellan-Jones asked Musk about Bezos. "Jeff who?" Musk responded.

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Mark Brake / Getty Images

Source: BBC

Then during an event in March, Space News Jeff Foust asked Bezos about his vision to have millions of people living and working in space colonies.

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Blue Origin

Source: Business Insider

Bezos seized the opportunity to rib Musk without naming him over his rivals vision of permanently settling Mars. (Musk has described a Mars settlement as a back-up plan for humanity in case anything tragic befalls Earth.)

BusinessInsider USA Images

SpaceX/YouTube

Source: Business Insider

"One thing I find very un-motivating is the kind of Plan B argument, where the Earth gets destroyed, where you want to be somewhere else. That I find very little... It doesnt work for me," Bezos told Foust.

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Alex Wong/Getty Images

Source: Business Insider

Bezos added: "We have sent robotic probes now to every planet in this solar system, and this is the best one. My friends who want to move to Mars? I say, Do me a favor, go live on the top of Mount Everest for a year first, and see if you like it because its a garden paradise compared to Mars."

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Courtesy of Shaunna Burke

More friction has arisen as both entrepreneurs plan to launch vast numbers of internet-providing satellites. Since at least 2015, Musk has spoken about a plan to create a global network of nearly 12,000 such satellites, called Starlink.

BusinessInsider USA Images

Mark Handley/University College London

Source: Business Insider

Amazon announced in April 2019 that it plans to launch Project Kuiper: a similar network of about 3,200 internet-providing satellites. Musk confronted Bezos on Twitter with the message: "@JeffBezos copy "

BusinessInsider USA Images

Bill Pugliano / Stringer / Getty Images

Sources: MIT Technology Review , Twitter

In May, Bezos debuted a concept for a private moon lander called Blue Moon. The spacecraft is being designed by Blue Origin in hopes of helping return NASA astronauts to the moon for the first time in decades.

BusinessInsider USA Images

Dave Mosher/Business Insider

Source: Business Insider

During his presentation (before Blue Moons unveiling), Bezos took a moment to indirectly criticize Musks Mars-settling plans yet again.

BusinessInsider USA Images

Dave Mosher/Business Insider

Bezos described the moon as a more realistic near-term destination. A slide in his presentation showed an image of Mars with the title "FAR, FAR AWAY." The slides notes said: "Round-trip travel on the order of years" and "No real-time communication."

BusinessInsider USA Images

NASA/JPL-Caltech; Dave Mosher/Business Insider

Sources: Business Insider , Blue Origin/YouTube

When asked about Bezos Blue Moon debut, Musk said he welcomed the competition. However, he added: "But putting the word Blue on a ball is questionable branding."

BusinessInsider USA Images

Dave Mosher/Insider

Source: Twitter

Hours later, Musk took the joke further: He edited a screenshot of a New York Times article about the spacecraft to read "balls" instead of "moon."

BusinessInsider USA Images

Elon Musk via Twitter

Sources: Twitter , Business Insider

The tech moguls are now sparring over a lucrative US Air Force contract. SpaceX recently sued the government agency after it awarded Blue Origin part of a $2.3 billion agreement for rocket development.

BusinessInsider USA Images

Win McNamee / Getty Images

Source: CNBC

But as they have done in the past, the men and the companies they founded will likely rise above such disputes and continue their prodigious push to remake spaceflight.

BusinessInsider USA Images

NASA/Flickr

SpaceX is currently toiling in south Texas to develop Starship: an enormous and fully reusable Mars rocket system. For now, the company is testing concepts for the vehicle with a steel prototype called Starhopper.

BusinessInsider USA Images

Dave Mosher/Business Insider

Source: Business Insider

Meanwhile, Blue Origin is working toward a 2021 debut of New Glenn: a partly reusable rocket that will enter the company into tangible competition with SpaceX and other launch providers.

BusinessInsider USA Images

Blue Origin

Elon Musk and Jeff Bezos are in an epic, years-long feud over space travel. Here's a timeline of the billionaires' most notable battles.

Bezos founded Blue Origin in 2000 as Amazons success surged.

Musk, meanwhile, used the money he earned from eBays purchase of PayPal to launch SpaceX in 2002.

In 2004, the two met for a friendly dinner and talked about rockets. Even then, though, there was an adversarial spirit. "I actually did my best to give good advice, which he largely ignored," Musk said of meeting Bezos.

For about a decade, as each company experimented with rocket designs on private land in Texas, the two men largely kept their criticisms of one another out of the public eye.

That changed in 2013, after NASA asked companies to submit pitches for how they might use Launch Complex 39A in Cape Canaveral, Florida. Apollo and space-shuttle missions once launched from that historic site, but NASA was no longer using it.

SpaceX told NASA it wanted to use the pad exclusively. But then Blue Origin and United Launch Alliance a rival of SpaceX filed a joint protest with the government. Musk dubbed the move a "phony blocking tactic."

SpaceX later said it was open to sharing the site with NASA and other private companies if necessary. By the end of 2013, NASA agreed to lease the launchpad to SpaceX.

Another bitter battle came less than a year later, this time over drone ships. Such boats are autonomous, flat-decked, and able to serve as landing pads for huge rocket boosters. The rocket segment can then be reused, saving millions of dollars.

Blue Origin filed a patent for the concept in 2010, and it was granted in 2014. Musk wasnt happy, since drone ships are key to SpaceXs plans to reuse boosters. SpaceX didnt want to pay Bezos company to use a drone ship.

SpaceX petitioned to invalidate Blue Origins patent, stating that "the rocket science claimed in the ... patent was, at best, old hat" by 2009. The judge ruled mostly in SpaceXs favor, and Blue Origin withdrew 13 of 15 claims in the patent.

SpaceX had a point the concept was even featured in the 1959 Soviet sci-fi film "Nebo Zovyot," or "The Sky Beckons."

Not long after SpaceX claimed victory, Musk and Bezos began clashing in public. In November 2015, Blue Origin landed its first reusable rocket, called the New Shepard. "The rarest of beasts a used rocket," Bezos tweeted with a video.

Musk couldnt help but chime in. "Not quite rarest. SpaceX Grasshopper rocket did 6 suborbital flights 3 years ago & is still around," he tweeted in response to Bezos.

Musk went even further with his one-up. He added that it takes 100 times more energy to launch something to geostationary orbit (about 22,236 miles up) which is what SpaceXs Falcon 9 rocket does than to suborbital space (about 62 miles high), where Blue Origins New Shepard goes.

In December 2015, SpaceX successfully landed its first orbital-class rocket booster on a drone ship. Bezos praised the company in a tweet...

... But with a side of shade. Referencing Blue Origins accomplishments with landing New Shepard, Bezos said: "Congrats @SpaceX on landing Falcons suborbital booster stage. Welcome to the club!"

The two billionaires also occasionally drop snide remarks about one another during press interviews. A few weeks after SpaceXs rocket-booster landing, for instance, the BBCs Rory Cellan-Jones asked Musk about Bezos. "Jeff who?" Musk responded.

Then during an event in March, Space News Jeff Foust asked Bezos about his vision to have millions of people living and working in space colonies.

Bezos seized the opportunity to rib Musk without naming him over his rivals vision of permanently settling Mars. (Musk has described a Mars settlement as a back-up plan for humanity in case anything tragic befalls Earth.)

"One thing I find very un-motivating is the kind of Plan B argument, where the Earth gets destroyed, where you want to be somewhere else. That I find very little... It doesnt work for me," Bezos told Foust.

Bezos added: "We have sent robotic probes now to every planet in this solar system, and this is the best one. My friends who want to move to Mars? I say, Do me a favor, go live on the top of Mount Everest for a year first, and see if you like it because its a garden paradise compared to Mars."

More friction has arisen as both entrepreneurs plan to launch vast numbers of internet-providing satellites. Since at least 2015, Musk has spoken about a plan to create a global network of nearly 12,000 such satellites, called Starlink.

Amazon announced in April 2019 that it plans to launch Project Kuiper: a similar network of about 3,200 internet-providing satellites. Musk confronted Bezos on Twitter with the message: "@JeffBezos copy "

In May, Bezos debuted a concept for a private moon lander called Blue Moon. The spacecraft is being designed by Blue Origin in hopes of helping return NASA astronauts to the moon for the first time in decades.

During his presentation (before Blue Moons unveiling), Bezos took a moment to indirectly criticize Musks Mars-settling plans yet again.

Bezos described the moon as a more realistic near-term destination. A slide in his presentation showed an image of Mars with the title "FAR, FAR AWAY." The slides notes said: "Round-trip travel on the order of years" and "No real-time communication."

When asked about Bezos Blue Moon debut, Musk said he welcomed the competition. However, he added: "But putting the word Blue on a ball is questionable branding."

Hours later, Musk took the joke further: He edited a screenshot of a New York Times article about the spacecraft to read "balls" instead of "moon."

The tech moguls are now sparring over a lucrative US Air Force contract. SpaceX recently sued the government agency after it awarded Blue Origin part of a $2.3 billion agreement for rocket development.

But as they have done in the past, the men and the companies they founded will likely rise above such disputes and continue their prodigious push to remake spaceflight.

SpaceX is currently toiling in south Texas to develop Starship: an enormous and fully reusable Mars rocket system. For now, the company is testing concepts for the vehicle with a steel prototype called Starhopper.

Meanwhile, Blue Origin is working toward a 2021 debut of New Glenn: a partly reusable rocket that will enter the company into tangible competition with SpaceX and other launch providers.

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