A recent study titled “Bright unintended electromagnetic radiation from second-generation Starlink satellites” has revealed that the latest generation of Starlink satellites is emitting unexpectedly strong electromagnetic radiation across a wide range of radio frequencies. This unintended radiation poses potential challenges for radio astronomy observations. A team of researchers used the LOFAR radio telescope to detect and characterize this radiation from both older and newer versions of Starlink satellites.

Background and Observations

In recent years, several companies have begun launching large numbers of satellites into low Earth orbit to provide global communications services. SpaceX’s Starlink constellation is the largest of these efforts, with thousands of satellites already in orbit and plans for tens of thousands more. While these satellite networks promise to expand internet access, they have raised concerns in the astronomy community about potential interference with observations.

The researchers used the LOFAR radio telescope in the Netherlands to observe Starlink satellites as they passed overhead. They conducted two one-hour observing sessions in July 2024, one covering frequencies from 10 to 88 MHz and another from 110 to 188 MHz. These frequencies are important for various types of radio astronomy observations.

Key Findings and Implications

The study found that the newest generation of Starlink satellites, known as v2-Mini and v2-Mini Direct-to-Cell (DTC), emit significantly stronger unintended radiation compared to the older v1.0 and v1.5 models. In some frequency ranges, the new satellites produced signals up to 32 times stronger than the older versions.

The unintended radiation from the new satellites was detected across a broad range of frequencies:

• Strong emissions between 40-70 MHz
• Bright signals from 110-188 MHz
• Peak emissions often occurring around 60-64 MHz

The strength of the unintended radiation varied considerably between individual satellites, even of the same model. Some v2-Mini satellites produced signals over 1000 times stronger than background noise levels at certain frequencies.

The researchers expressed concern about how this unintended radiation could affect radio astronomy observations:

• Radio telescopes may need to discard data from time periods and frequency ranges affected by satellite passes.
• Many modern radio telescopes are designed to observe large areas of the sky simultaneously, increasing the likelihood that observations will be impacted at all times.
• For radio telescope arrays with multiple antennas, satellite signals may not average out over long observations, potentially introducing errors in measurements of large-scale cosmic structures.

Technical Details and Broader Context

The researchers characterized several interesting properties of the unintended radiation, including spectral combs with regular patterns of peaks in frequency. These patterns differed between satellite models and may provide clues about the onboard systems generating the radiation.

The study notes that current international regulations on satellite transmissions focus on intentional communications signals. The type of unintended radiation detected in this study falls outside existing regulatory frameworks. The researchers suggest that new guidelines may be needed to address unintended emissions from satellites.

This study is part of a larger effort to understand how the rapid growth of satellite constellations may impact astronomy. The astronomy community is actively engaging with satellite operators and regulators to find solutions that balance the benefits of global communications with the need to protect Earth and space-based observatories.

Summary

The detection of strong, unintended radio emissions from the latest generation of Starlink satellites highlights the evolving challenges faced by radio astronomers in an increasingly crowded orbital environment. While satellite constellations promise significant benefits, careful consideration is needed to mitigate their potential impact on scientific observations.

The researchers emphasize the need for continued study of satellite emissions, engagement with operators to explore mitigation strategies, and potential updates to regulatory frameworks. With proper coordination between the satellite industry and the scientific community, solutions may be found to support both global communications and groundbreaking astronomical research.