On Tuesday, Elon Musk tweeted a message to Jeff Bezos.
In response to an article from the MIT Technology Review that announced Amazon's plans to launch more than 3,000 internet-providing satellites, Musk called Bezos a copycat, with the "cat" portion of the word replaced with a cat emoji.
Presumably, that's because in February 2018, Musk's SpaceX launched satellites to provide "global broadband" to the "least served" areas around the world.
And according to CNBC, Bezos hired a SpaceX executive, Rajeev Badyal, to run the Amazon's satellite project after Musk fired him.
There also seems to be a friendly competitive spirit between Musk and Bezos when it comes to their aerospace businesses, SpaceX and Blue Origin.
Last year, Bezos wished SpaceX luck with a Falcon Heavy launch. Musk's response then, too, was cheeky — he included an emoji blowing a kiss along with his thanks. Bezos then tweeted rocket emojis back at Musk.
Musk and Bezos, after all, are both billionaires with a mission to make it possible for people to live in space.
Fundamentally, SpaceX's goal is to build re-usable rockets and spacecraft so humans can inhabit other planets, namely Mars.
For Musk, life on Mars would start with a single outpost: "Build up the base, starting with one ship, then multiple ships, then start building out the city, then making the city bigger, and even bigger. And yeah, over time terraforming Mars and making it really a nice place to be," he said in September.
Bezos's Blue Origin is focused on building the infrastructure to make it possible for future generations of humans to iterate on space technology and build new companies inexpensively.
Bezos imagines a future where humans live in free-floating space pod colonies.
Amazon, Blue Origin and representatives for Bezos and Musk did not immediately respond to CNBC Make It's request for comment.
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