Imagine a future where our view of the cosmos is forever marred by streaks of artificial light, obscuring the very stars and galaxies we seek to study. This is the stark reality we face as satellite mega-constellations proliferate in low-Earth orbit, threatening to contaminate space-based observations. A groundbreaking analysis by NASA researchers (https://www.nature.com/articles/s41586-025-09759-5) has sounded the alarm: unless we curb satellite light pollution, the future of astronomical research hangs in the balance.
But here's where it gets controversial: while these mega-constellations, such as SpaceX’s Starlink (https://www.starlink.com/), Amazon’s Kuiper (https://www.aboutamazon.com/what-we-do/devices-services/project-kuiper), and Eutelsat’s OneWeb (https://oneweb.net/), have revolutionized global internet access, their rapid expansion—from 2,000 satellites in 2019 to 15,000 today—is clashing with the needs of space-based observatories. These satellites share the same orbital space as telescopes like NASA’s Hubble Space Telescope, leaving them vulnerable to reflected light that renders images unusable, even with anti-reflective coatings (https://physicsworld.com/a/dark-coated-starlink-satellites-are-better-but-not-perfect-say-astronomers/).
And this is the part most people miss: while the impact of these constellations on ground-based astronomy has been studied (https://physicsworld.com/a/starlink-satellite-emissions-interfere-with-radio-astronomy/), their effect on space-based telescopes has been largely overlooked—until now. NASA’s Alejandro Borlaff and his team simulated the impact on four observatories: Hubble, the upcoming SPHEREx (launching 2025), the proposed ARRAKIHS mission, and China’s Xuntian telescope. All operate or will operate between 400 and 800 km above Earth.
The findings are alarming: if satellite numbers reach the projected 56,000 by the end of the decade, nearly 40% of Hubble’s images and a staggering 96% of images from the other telescopes could be contaminated. For context, the average number of satellites per exposure would skyrocket to 2.14 for Hubble, 5.64 for SPHEREx, 69 for ARRAKIHS, and 92 for Xuntian.
One proposed solution? Orbiting satellites at lower altitudes than telescopes, making them dimmer. But here’s the catch: this could harm Earth’s ozone layer. Is this a trade-off we’re willing to make?
Katherine Courtney, chair of the Global Network on Sustainability in Space (https://gnosisnetwork.org/), emphasizes the irony: without astronomy, the modern space economy “simply wouldn’t exist.” Astronomy has driven advancements in orbital mechanics and technology that underpin today’s satellite industry. Yet, the very growth of this industry now threatens its scientific roots. Courtney calls for urgent dialogue between astronomers and satellite operators to find a balance, ensuring both commercial and scientific endeavors can thrive in space.
But here’s the question we must ask: Can we innovate our way out of this crisis, or will the night sky—both on Earth and in space—become a casualty of progress? Share your thoughts in the comments below. For deeper insights, watch the Physics World Live panel discussion featuring Courtney and Alice Gorman from Flinders University (https://register.gotowebinar.com/#register/7305432780752341593?source=Physics+World+Landing+Page).
