Satellite Constellations Polluting Wavelength Bands Critical for Radio Astronomy, New Research Finds
Constellations of satellites orbiting the Earth are causing significant interference with the wavelength bands essential for radio astronomy, according to recent research. Scientists have discovered that the electronics onboard SpaceX’s Starlink satellites are emitting low-frequency radio waves, beyond their designated downlink bands. This interference has the potential to impede astronomical observations.
Engineer Federico Di Vruno of the SKA Observatory and the International Astronomical Union stated, “This study represents the latest effort to better understand satellite constellations’ impact on radio astronomy. Previous workshops on Dark and Quiet Skies theorized about this radiation, but our observations confirm it is measurable.”
As the number of satellites in Earth’s orbit continues to increase, concerns about their impact on space exploration intensify. Currently, SpaceX has approximately 4,365 small internet satellites in orbit, with plans for thousands more. Other companies such as OneWeb and Amazon also have significant satellite constellations.
SpaceX did address concerns regarding visible light pollution by designing dimmer satellites. However, this primarily addresses concerns related to visible light wavelengths and neglects the broader branch of radio astronomy, which is critical to our understanding of the universe.
The specific radio frequencies used by the satellites for communication downlink, between 10.7 and 12.7 gigahertz, have already raised concerns. However, scientists suspected that the satellites might unintentionally emit radio waves outside of this range, prompting the investigation by Di Vruno and his colleagues.
To study this interference, the researchers utilized the LOw-Frequency ARray (LOFAR) in Europe, which consists of around 20,000 radio antennas across 52 locations. With this high level of sensitivity, they observed 68 satellites from the Starlink constellation and detected electromagnetic leakage.
Astronomer Cees Bassa of ASTRON, the Netherlands Institute for Radio Astronomy, explained, “With LOFAR, we detected radiation between 110 and 188 MHz from 47 out of the 68 satellites that were observed. This frequency range includes a protected band between 150.05 and 153 MHz specifically allocated to radio astronomy by the International Telecommunications Union.”
Although the emitted radiation is unintentional, originating from the satellites’ electronics, it is not in violation of any current regulations. On Earth, the International Electrotechnical Commission imposes stringent restrictions on electrical devices to control electromagnetic interference, but these rules do not apply in space.
Currently, the effects of the interference are relatively minor. However, with the increasing number of satellites emitting unintentional radio signals, the impact will become more significant over time.
Fortunately, a solution is already being developed. The researchers have reached out to SpaceX, which is actively working on ways to minimize or eliminate this unintended leakage. As satellite constellation technology is still in its early stages, adjustments can be made to future designs while regulators work to address the unexpected gap in official rules.
Astronomer Michael Kramer of the Max Planck Institute for Radio Astronomy and the Astronomische Gesellschaft in Germany commented, “The present study highlights an example of the various channels of how technology development may have unforeseen side effects on astronomy. With SpaceX setting an example, we are now hoping for the broad support from the whole satellite industry and regulators.”
The research findings have been published in the journal Astronomy & Astrophysics.