Elon Musk has enraged astronomers around the world, who are warning his SpaceX company is putting the future of astronomy at risk.
The notorious billionaire plans to encircle the world with 12,000 Starlink communications satellites, and launched the first 60 into orbit a few days ago.
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The satellites are high-reflective, and they're currently lighting up the night sky with a spectacular 'train' of lights.
But scientists fear his plan for space domination could have dramatic adverse effects on their research.
A number of senior figures say the satellites will cause a massive spike in light pollution in the sky, affecting the use of large, sensitive ground-based telescopes.
"The potential tragedy of a mega-constellation like Starlink is that for the rest of humanity it changes how the night sky looks," Ronald Drimmel, from the Turin Astrophysical Observatory in Italy, told Forbes.
"Starlink, and other mega constellations, would ruin the sky for everyone on the planet."
Mark McCaughrean, the senior advisor for science and exploration at the European Space Agency, warns a drastic increase in visible satellites is a "chilling thought".
"The more I think about this, the more of a disaster it seems and not just for astronomers," he tweeted.
"Just trying desperately to scramble for any possible way this can go well," agreed science writer Mika McKinnon.
US astronomy student Victoria Girgis took a photo of what they look like passing in front of her telescope with a 25-second exposure. The result was a night sky smeared with satellites.
"I took this picture as the StarLink satellites crossed in front of a group of galaxies I was imaging for public education," she tweeted.
And Royal Institution of Australia lead scientist Alan Duffy, an astronomer at Swinburne University, warned the completion of the Starlink network will only make things worse.
"A full constellation of Starlink satellites will likely mean the end of Earth-based microwave-radio telescopes able to scan the heavens for faint radio objects," Duffy told ScienceAlert.
"The enormous benefits of global internet coverage will outweigh the cost to astronomers, but the loss of the radio sky is a cost to humanity as we lose our collective birthright to see the afterglow of the Big Bang or the glow of forming stars from Earth."
Musk has defended his actions, variously arguing that the International Space Station also has lights, that his satellites won't have any impact, SpaceX is working to mitigate any impacts, that even if they did have an impact it was for the "greater good", and scientists need to upgrade their equipment anyway.
"Potentially helping billions of economically disadvantaged people is the greater good," he tweeted.
"We need to move telescopes to orbit anyway. Atmospheric attenuation is terrible."