Observations by the LOFAR (Low Frequency Array) radio telescope showed in 2023 that first-generation Starlink satellites emit unintended radio signals (or “UEMR” for Unintended ElectroMagnetic Radiation) that can interfere with astronomical observations.
A new study, dated September 18, 2024, involving CNRS researchers from Observatoire de Paris - PSL, operating LOFAR [1] finds that the second-generation “V2 mini” Starlink emits up to 32 times more, and in a wider range of frequencies, than the first generation. It thus threatens to blind radio telescopes and prohibit research vital to our knowledge of the Universe.
Starlink’s EMRUs are 10 million times more intense than the faintest sources observed by LOFAR. They exceed the levels recommended by the International Telecommunication Union in the 150.5-153 MHz band allocated to radio astronomy, and potentially even the usual electromagnetic compatibility standards used for commercial electronic equipment.
The threat is growing with Starlink’s launch of 40 mini V2 satellites a week, and the development of numerous other low-orbit satellite constellations.
LOFAR is the world’s largest telescope observing at low radio frequencies. It comprises 52 stations, centered in the Netherlands but spread across Europe, including one at the Observatoire radioastronomique de Nançay (ORN).
At ORN, the LOFAR station is complemented by the NenuFAR radio telescope, which confirms LOFAR observations at low frequencies.
The animation below shows emissions from a Starlink satellite scrolling through NenuFAR’s field of view.
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Their power and speed will particularly affect the observation of bursts and fast transients from many astrophysical sources, such as exoplanets, novae and so on.
The authors of the study hope that their measurements will help operators to identify the causes of their UEMRs.
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Laboratory involved
- Laboratoire d’études spatiales et d’instrumentation en astrophysique (LESIA - Observatoire de Paris - PSL)
Supervision : Observatoire de Paris - PSL / CNRS / Sorbonne Univ / Univ Paris Cité
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Scientific reference
Bright unintended electromagnetic radiation from second-generation Starlink satellites, Bassa et al., A&A, 689 (2024) L10.
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[1] LOFAR is the largest and most sensitive radio telescope observing the lowest frequencies accessible from the ground, from 10 to 240 MHz