Astronomers are warning that their view of the Universe could be under threat.
From next week, a campaign to launch thousands of new satellites will begin in earnest, offering high-speed internet access from space.
But the first fleets of these spacecraft, which have already been sent into orbit by US company SpaceX, are affecting images of the night sky.
They are appearing as bright white streaks, so dazzling that they are competing with the stars.
Scientists are worried that future “mega-constellations” of satellites could obscure images from optical telescopes and interfere with radio astronomy observations.
Dr Dave Clements, an astrophysicist from Imperial College London, told BBC News: “The night sky is a commons – and what we have here is a tragedy of the commons.”
The companies involved said they were working with astronomers to minimise the impact of the satellites.
Why are so many satellites being launched?
It’s all about high-speed internet access.
Instead of being constrained by wires and cables, satellites can beam internet access down to the ground from space.
And if you have lots of them in orbit, it means even the most remote regions can get connectivity.
To give you an idea of the numbers, there are currently just 2,200 active satellites flying around the Earth.
But as of next week, the Starlink constellation – a project by US company SpaceX – will start sending batches of 60 satellites into orbit every few weeks. This will mean about 1,500 satellites have been launched by the end of next year, and by the mid-2020s there could be a fleet of 12,000.
UK company OneWeb are aiming for about 650 satellites – but this could rise to 2,000 if there is enough customer demand.
While Amazon have a constellation of 3,200 spacecraft planned.
Why are astronomers worried?
In May and November, Starlink sent 120 satellites into orbits below 500km.
But stargazers were concerned when the spacecraft appeared as bright white flashes on their images.
