Constellation of satellites could threaten astronomy research and ruin stargazing for enthusiasts, say experts
More than 400 Space X's Starlink satellites are orbiting our Earth — and over 100,000 others are expected to join them in the coming years. This swam of objects could challenge observations of the cosmos and also ruin stargazing for space enthusiasts, according to a new report.
In 2019, Space X launched its first batch of 60 Starlink communication satellites to Earth's low orbit with the mission to offer high-speed Internet, even to the most remote regions in the world. OneWeb has launched 74 satellites so far. Facebook and Amazon have also joined the race. But astronomers have raised concerns over the brightness of the constellation of satellites. “I think it’s commendable and very impressive engineering to spread the information and opportunities made possible by internet access,” says Megan Donahue (Michigan State University), President of the American Astronomical Society (AAS). “But I, like many astronomers, am very worried about the future of these new bright satellites.”
The new report focuses on understanding the potential impacts of a megaconstellation of Internet satellites. A swarm of objects in the low-Earth orbit could interfere with ground-based telescopes that scan the night skies to detect threats from near-earth objects and to unlock the mysteries of the universe. “Rubin Observatory and the giant 30-meter telescopes coming online in the next decade will substantially enhance humankind’s understanding of the cosmos,” says SATCON1 co-chair Jeff Hall from Lowell Observatory and chair of the AAS Committee on Light Pollution, Radio Interference, and Space Debris. “For reasons of expense, maintenance, and instrumentation, such facilities cannot be operated from space. Ground-based astronomy is, and will remain, vital and relevant.”
Depending on their altitude and brightness, constellation satellites could spoil starry nights for amateur astronomers, astrophotographers, and other nature enthusiasts. But if they are located below 600 kilometers, the interference could be lesser. "But satellites at higher altitudes, such as the constellation planned by OneWeb that will orbit at 1,200 kilometers (about 750 miles), maybe visible all night long during summer and for much of the night in other seasons," they warned.
The report follows a virtual workshop that had more than 250 scientists, engineers, satellite operators and other stakeholders in attendance. "Even though we’re still at an early stage of understanding and addressing the threats posed to astronomy by large satellite constellations, we have made good progress and have plenty of reasons to hope for a positive outcome," says AAS President Paula Szkody of the University of Washington, who participated in the workshop.
Experts have highlighted a few measures to lower the blow to astronomy. The first, they say, is to launch fewer or no low-Earth orbit satellites. "However impractical or unlikely, this is the only option identified that can achieve zero astronomical impact," they note. They recommend that satellites remain at an orbital altitude lower than about 600km. They also called for darkening the objects or using sunshades to shadow their reflective surfaces and controlling satellite's orientation in space to reflect less sunlight to Earth. Making accurate satellite orbital information more available to observers will help avoid interference, they added.