2024-09-19 20:22:25
Observations by the LOFAR (Low Frequency Array) radio telescope last year showed that the first-generation Starlink satellites emit unwanted radio waves that can interfere with astronomical observations. This was announced by the Institute of Astronomy with National Astronomical Observatory Rozhen (NAO-BAS).
New studies with the LOFAR radio telescope, the largest low-frequency radio telescope on Earth, have shown that the second generation Starlink V2-mini satellites emit up to 32 times brighter spurious radio waves than previous generation satellites, as potentially “blinding” radio telescopes in low radio frequencies and thus interfering with vital studies of the universe. Bulgaria is a co-founding member of the European research infrastructure consortium LOFAR ERIC, which manages the telescope. A LOFAR observation station is being built near the Rozhen National Astronomical Observatory, which is expected to be operational by the end of 2025, writes BTA.
In recent years, the number of satellites launched into low Earth orbit (LEO) has grown rapidly as a result of the rapid commercialization of space and advances in satellite technology. As of 2019, companies such as SpaceX and OneWeb have launched hundreds to thousands of satellites, especially for communications purposes. Plans indicate that the number of satellites in orbit could exceed 100,000 by the end of the decade. The growing emissions of radio waves from satellites in LEO raise serious concerns for the future of astronomical research.
The study showing this hazard was conducted using the LOFAR radio telescope in two extensive one-hour observing sessions on July 19, 2024 in radio frequencies above and below the FM range (98-108 MHZ) used by radio stations. During these observations, the team detected unwanted electromagnetic radiation (UEMR) from almost all Starlink satellites observed, both first and second generation.
“With LOFAR, we have started a program to observe spurious emissions from satellites belonging to different constellations, and our observations show that the second generation Starlink satellites emit stronger emissions and do so over a wider range of radio frequencies than the first generation of satellites,” says lead study author Kees Bassa of ASTRON (Netherlands Institute for Radio Astronomy).
The analysis reveals that these newer satellites emit up to 32 times brighter unintended radio waves than the first generation, with levels potentially exceeding internationally regulated interference thresholds set for intentional emissions and even more relaxed ground-based electromagnetic compatibility standards.
“Compared to the faintest astrophysical sources we observe with LOFAR, the UEMR from the Starlink satellites is 10 million times brighter. This difference is similar to the faintest stars visible to the naked eye and the brightness of the full Moon.” As SpaceX launches about 40 second-generation Starlink satellites every week, this problem is becoming more and more serious,” adds Kees Bassa.
The research highlights the need for stricter regulations around unwanted satellite emissions to preserve the integrity of radio astronomy observations that are vital to understanding the universe and our place in it. The study serves as a clarion call to action to preserve the future of astronomy in the face of advancing satellite technology.
“Humanity is clearly approaching a tipping point where we must take action to preserve our sky as a window to explore the universe from Earth. Satellite companies are not interested in producing this unwanted radiation, so minimizing it must also be a priority in their sustainable space policies,” says Federico Di Vruno of the SKA observatory. “Starlink is not the only big player in LEO, but they have a chance to set the standard in this area,” he adds.
Researchers stress that while second-generation satellites are designed to improve connectivity and provide communications services, unintended radio emissions are a growing threat to the integrity of astronomical observations. As the consequences of such interference become increasingly apparent, collaboration between satellite companies, regulatory agencies, and the astronomical community is essential to develop effective mitigation strategies.
In the Netherlands, one of Europe’s most populous countries, ASTRON operates LOFAR, the world’s most sensitive low-frequency telescope. This is only possible as a result of the regulatory support of Dutch local, provincial and national agencies. Municipalities consult with ASTRON and support the institute by advising others.
Prof. Jessica Dempsey, ASTRON’s General and Scientific Director stated: “Since LOFAR’s inception more than a decade ago – when we were told we would soon be hard to observe due to radio interference – regulatory support and productive collaboration with industry has been shared over 1000 individual examples of cooperation with dozens of groups, companies, infrastructures, agencies and individuals throughout the country”.
And this relationship is not only one-sided. Smart technologies for detecting weak signals in space have powered technological advances in industry and society, from GPS to WiFi. We don’t just exist together, we evolve together. We have solutions for this symbiosis in space too – we just need regulators to support us and industry to do its part. Without mitigation from such activities, very soon the only constellations we will see will be man-made.