Starlink Satellites Interference Threaten Astronomical Research

The rapid expansion of Starlink's satellite network, operated by SpaceX, is causing significant interference with astronomical observations, particularly with radio telescopes. This issue, highlighted in several recent studies, poses a growing challenge to the scientific community, threatening critical research into the universe's mysteries.

Starlink currently operates more than 6,300 satellites in low Earth orbit (LEO), with that number expected to grow to over 12,000 in the coming years. While the primary function of these satellites is to provide high-speed internet to underserved communities globally, they are also inadvertently emitting unintended electromagnetic radiation (UEMR). These emissions interfere with sensitive radio telescopes, compromising their ability to detect faint signals from distant celestial objects.

A recent study conducted by the Netherlands Institute for Radio Astronomy (ASTRON) and published in Astronomy & Astrophysics has shown that second-generation V2 Starlink satellites emit up to 32 times more UEMR than the first-generation satellites. These findings were obtained using the LOFAR (Low-Frequency Array) radio telescope, the most sensitive low-frequency telescope in the world. Researchers conducted observations in July 2024, detecting unintended emissions from almost all Starlink satellites in view. 

"With LOFAR, we started a program to monitor unintended emissions from different satellite constellations. Our observations show that second-generation Starlink satellites emit stronger emissions over a larger range of radio frequencies compared to the first generation," said Cees Bassa, Astronomer and Researcher, ASTRON.

Radio telescopes like LOFAR, which operate by detecting extremely faint signals from the far reaches of the universe, are being "blinded" by emissions from the Starlink satellites. Bassa noted that UEMR from Starlink satellites is "10 million times brighter" than some of the faintest astrophysical sources LOFAR observes. To put this into perspective, the brightness difference is akin to comparing the faintest stars visible to the naked eye with the full moon.

"Since SpaceX is launching about 40 second-generation Starlink satellites every week, this problem is becoming increasingly worse," added Bassa.

This issue is not limited to SpaceX's Starlink network; other satellite constellations, such as those operated by OneWeb and Amazon's Kuiper project, are also expected to contribute to the growing interference problem. Although SpaceX made modifications to its first-generation Starlink satellites to reduce emissions, the newer generation appears to have reversed these efforts. 

"While the generation 1 satellites indeed got dimmer in the last year, the new generation unfortunately seems to be brighter again," said Benjamin Winkel, Scientist, Max Planck Institute for Radio Astronomy. 

The concern among the astronomical community is that the number of orbiting satellites could exceed 100,000 by 2030, amplifying the interference problem. The unintended emissions from these satellites interfere not only with radio telescopes but also with optical observations, leaving smears on images and corrupting valuable data.

The scientific community has called for stricter regulations to control these emissions and mitigate their impact on space research. Currently, there are few regulations governing satellite operators regarding unintended radiation in space. On the ground, cellphone networks and other sources of radio pollution are tightly controlled by regulatory bodies such as the International Telecommunications Union (ITU). However, space-based emissions remain largely unregulated, leaving the scientific community dependent on goodwill and cooperation from satellite operators.

"Since LOFAR began, we were told we would soon struggle to observe because of radio interference. The regulatory support and collaboration with industry have been vital in mitigating these issues. We have the solutions for symbiosis in space as well—we just need regulators and industry to meet us halfway,"said Prof. Jessica Dempsey, General and Scientific Director, ASTRON.