Cutting-edge research has shed light on the concerning issue of satellite constellations impeding radio astronomy by inundating Earth’s orbital skies with an abundance of satellites. The latest study, conducted by engineer Federico Di Vruno from the SKA Observatory and the International Astronomical Union, represents a significant effort to comprehend the effects of these constellations on radio astronomy.
Previous discussions on Dark and Quiet Skies had postulated the presence of radiation from satellite constellations, and now these assumptions have been substantiated by actual observations. Our skies are becoming increasingly crowded, posing a growing challenge to the field of space exploration. With an estimated 4,365 Starlink satellites already orbiting Earth and a multitude of others in the pipeline, spearheaded by companies like SpaceX, OneWeb, and Amazon, the impact on our ability to conduct astronomy research is cause for concern.
While SpaceX responded to concerns about visible light pollution by designing new, dimmer satellites, it is crucial to acknowledge that visible wavelengths constitute only a fraction of Earth-based astronomy. The field of radio astronomy, which is arguably more significant, is now facing potential difficulties.
The allocated downlink bands of these satellites, particularly within the radio frequencies between 10.7 and 12.7 gigahertz used in Europe, have already raised concerns among scientists. However, researchers suspected that the satellites might emit unintentional radio waves outside of the designated band. This prompted Di Vruno and colleagues to embark on a comprehensive investigation.
Leveraging the power of the LOw Frequency ARray (LOFAR) network in Europe, which encompasses approximately 20,000 radio antennas across 52 locations, the researchers meticulously observed 68 Starlink satellites. Their findings unequivocally confirmed the existence of electromagnetic leakage.
“We detected radiation between 110 and 188 MHz from 47 out of the 68 satellites that were observed using LOFAR,” reveals astronomer Cees Bassa from ASTRON, the Netherlands Institute for Radio Astronomy. “This frequency range includes a protected band between 150.05 and 153 MHz specifically allocated to radio astronomy by the International Telecommunications Union.”
The emission causing concern appears to be an unintentional byproduct of the satellites’ electronic systems. While it does not violate any regulations, it is important to note that the International Electrotechnical Commission’s stringent restrictions on electrical devices, which aim to control electromagnetic interference, do not apply in the vastness of space.
Although the present impact remains relatively minor, it is imperative to acknowledge that as the number of satellites emitting these unintended radio signals increases, the brightness of the interference will intensify accordingly.
However, a solution is already on the horizon. The research team has reached out to SpaceX, which is actively developing methods to minimize or eliminate this unintended leakage. Furthermore, as we are only at the nascent stage of satellite constellation technology despite the thousands of satellites already in orbit, addressing this issue early on allows for adjustments in future designs while regulators work to fill the unanticipated gap in official guidelines.
“This study exemplifies the potential unintended consequences of technological advancements on astronomy,” remarks astronomer Michael Kramer from the Max Planck Institute for Radio Astronomy and the Astronomische Gesellschaft in Germany. “With SpaceX taking the lead, we hope to gain broad support from the entire satellite industry and regulators.”
The findings of this groundbreaking research have been published in the esteemed journal Astronomy & Astrophysics.