From his vantage point 250 miles above Earth aboard the International Space Station (ISS), NASA astronaut Don Pettit has been treating us to a spectacular series of images. His latest offering is particularly striking: a breathtaking panorama of distant stars, the twinkling city lights of our planet, and a constellation of what Pettit aptly describes as ‘cosmic fireflies.’ These aren’t fireflies, of course, but rather the Starlink satellites deployed by Elon Musk’s SpaceX, their surfaces reflecting sunlight as they orbit hundreds of miles above the ISS.
Since their initial deployment in 2019, over 6,700 Starlink satellites have joined the ranks of SpaceX’s low-Earth orbit mega-constellation. With permission to launch up to 12,000, and ambitions to deploy a staggering 42,000, the number of these ‘cosmic fireflies’ visible from the ISS – and indeed from Earth – is set to explode. This isn’t just a SpaceX phenomenon; other companies, such as Amazon, are also planning their own large-scale satellite internet projects, promising a future night sky increasingly populated with artificial satellites.
But the proliferation of these satellites isn’t simply a matter of aesthetic concern. The increasing brightness of these satellites, caused by sunlight reflecting off their surfaces, is significantly impacting ground-based astronomical observations. Astronomers have voiced serious concerns for years about the interference with their ability to study the deep cosmos using ground-based telescopes. This problem has intensified since SpaceX began launching its newer, V2 Starlink satellites in February 2022, with reports of disruption extending to radio astronomy observations due to electromagnetic radiation emitted by the satellites.
SpaceX launches approximately 40 of these second-generation satellites every week, exacerbating the issue. Professor Jessica Dempsey, director of ASTRON (Netherlands Institute for Radio Astronomy), recently warned the BBC that the situation poses a significant threat to ground-based astronomy. “If it continues, without the sort of mitigation to make these satellites quiet, then it does become an existential threat for the kinds of astronomy we do,” she stated, emphasizing the far-reaching impact across different wavelengths and observational methods.
SpaceX has undertaken efforts to mitigate these concerns, implementing measures to reduce the satellites’ brightness. However, the effectiveness of these measures, particularly for radio astronomy, remains a subject of ongoing debate and skepticism among astronomers. The stunning image captured by Don Pettit serves as a visual representation of this complex issue – a captivating view from space, juxtaposed with the growing challenges faced by astronomers on the ground striving to unravel the mysteries of the universe. The future of astronomical observation hangs in the balance, highlighting the need for a collaborative approach between commercial space ventures and the scientific community to safeguard the future of ground-based astronomy.
