One of the biggest changes in our low Earth orbit (LEO) environment comes from satellite megaconstellations. A recent study in Nature highlights concerns over how these massive fleets of satellites impact astronomy. Companies like SpaceX, OneWeb, and Amazon, as well as governments in China and the U.S., plan to launch thousands of satellites into orbit.
Researchers from NASA Ames Research Center explain that these satellites reflect light, interfering with astronomical images taken both on Earth and in space. They worry about the impact on observatories like NASA’s SPHEREx and the European Space Agency’s ARRAKIHS, as well as China’s new Xuntian telescope.
Between 2018 and 2021, around 4.3% of images from the Hubble Space Telescope already showed trails from artificial satellites. With projections of megaconstellations far surpassing current satellite numbers, this interference could become much more common. SpaceX, for instance, recently launched its 3,000th Starlink satellite, nearing its goal of 30,000.
China is also ramping up its satellite efforts, aiming for a fleet of 12,992 Guowang satellites, which were detailed in filings reviewed by Ars Technica.
Experts suggest some mitigation strategies, like limiting the collection of images during dawn and dusk when satellite reflections are most apparent. However, they argue that these solutions might not be enough to protect the quality of astronomical observations.
A forecast in the study predicts that 96% of exposures captured by next-generation telescopes like SPHEREx will show at least one satellite trail. This raises significant concerns, as many valuable astronomical observations could be compromised.
SpaceX has attempted to address these issues by working with the astronomy community on brightness control measures. They’ve stated, “While SpaceX is the first large constellation operator to tackle satellite brightness, we won’t be the last.” Their aim is to set a standard that future satellite operators can follow.
However, not all solutions are foolproof. Some strategies, such as adjusting satellite orientation to reduce reflections, may inadvertently increase visibility to space telescopes. If satellites lose control as they near the end of their life cycle, they could reflect even more light, complicating the task for astronomers.
These developments highlight a growing tension between advancing technology and preserving our ability to explore the universe. As the number of satellites continues to rise, the astronomical community faces challenges that will need careful consideration and creative solutions.
For those interested in the specifics of satellite impact on astronomy, you can find the original study in Nature here.
