Astronomers are concerned that SpaceX’s satellites will streak across the sky Victoria Girgis/Lowell Observatory

We are entering the age of satellite constellations, and astronomers are worried. On 23 May, SpaceX launched 60 communications satellites, the first in a planned fleet of 12,000.

In the following days, the Starlink satellites moved in a bright line through the sky. Many astronomers on social media expressed concerns about how these shining projectiles would affect observations of the night sky, hurtling through images of the stars and creating streaks that are difficult or impossible to remove.

Now things have stepped up a notch. The International Astronomical Union, a key ruling body when it comes to the night sky, has released a statement echoing those concerns and calling for regulation of these sorts of satellite constellations.


Aside from the Starlink satellites, OneWeb and Amazon are working on similar ideas for huge numbers of satellites to provide worldwide internet. Even if the satellites are not visible to the naked eye, they will certainly be visible to telescopes making precise astronomical observations.

The visible light isn’t the only problem: the satellites use radio signals to communicate, which could interfere with observations in those frequencies. “Recent advances in radio astronomy, such as producing the first image of a black hole… were only possible through concerted efforts in safeguarding the radio sky from interference,” the IAU statement says. Too many satellites emitting radio waves could endanger future studies.

SpaceX CEO Elon Musk tweeted shortly after the launch, “We’ll make sure Starlink has no material effect on discoveries in astronomy,” but it is unclear how that will be possible with thousands of satellites hurtling through the sky all the time. The IAU statement urges satellite designers and policymakers to take a closer look at the potential impacts of satellite constellations on astronomy and how to mitigate them.

“We also urge appropriate agencies to devise a regulatory framework to mitigate or eliminate the detrimental impacts on scientific exploration as soon as practical,” the statement says. “We strongly recommend that all stakeholders in this new and largely unregulated frontier of space utilisation work collaboratively to their mutual advantage.”

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