Recent space station inhabitant Don Pettit has shared a remarkable video showing dozens of orbiting Starlink satellites streaking across the dawn sky, photobombed by comet C/2024 G3 (ATLAS).

Captured from the International Space Station (ISS) during his stay there earlier this year, the footage, which also includes a part of the station at the bottom of the frame, clearly shows a number of SpaceX’s Starlink internet satellites moving from left to right in low-Earth orbit, and what appears to be the comet traveling in the opposite direction, far from our planet. 

The difference in direction is due to the relative motion of the satellites, which orbit Earth and reflect pre-dawn sunlight, and the comet, which is distant and moving along its own trajectory across the sky. 

SpaceX began deploying its Starlink internet satellites in 2019 and currently has around 8,000 of them in orbit, making it the world’s largest satellite constellation. The Elon Musk-led company is aiming to deploy another 4,000 satellites, though the final constellation could expand to as many as 42,000 satellites.

The more Starlink satellites SpaceX deploys, the wider the broadband coverage and the more reliable the service becomes. Starlink currently serves broadband internet to around 120 countries and territories, with more than 6 million customers on its books. 

But there’s also a cost to having such a large constellation. Astronomers, for example, have been complaining for years that the growing number of Starlink satellites is interfering with their observations of deep space. 

The issue concerns sunlight reflecting off the satellites’ surfaces. SpaceX has attempted to reduce the brightness of the reflected light by coating the satellites in a dark material, and also by adding reflective film to redirect the sunlight away from Earth.

But that’s not the only problem. Starlink satellites also emit radio signals that can interfere with sensitive radio astronomy observations, making it harder for astronomers to study the universe at certain wavelengths.

As for Comet C/2024, it won’t be appearing in other ISS videos anytime soon. The comet made its closest pass to Earth on January 13, coming within 8.7 million miles (around 14 million km) of our planet. But it’s not expected to return for hundreds of thousands of years, so this particular flyby was a very rare approach.

Interested to see more of Don Pettit’s work? Then check out this collection of his best imagery from his most recent orbital mission.