Swarms of satellites orbiting Earth are emitting more radiation than ever before in protected wavelength ranges. In fact, the second-generation Starlink satellites, known as v2mini and v2mini Direct-to-Cell, emit 32 times more radiation than their predecessors.

This is a problem because some of the radiation they emit is in the radio wavelength range, which is supposed to be clean for radio astronomy purposes. When the issue was first raised in 2023, SpaceX said it was working on a solution. Now, with 6,398 separate satellites in orbit at the time of writing, the problem has gotten even worse.

“We have started a program to monitor unwanted emissions from satellites belonging to different constellations, and our observations show that the second-generation Starlink satellites emit stronger radiation than the first-generation satellites, and do so over a wider range of radio frequencies,” says astronomer Cess Bassa from the Netherlands Institute for Radio Astronomy (ASTRON).

“Compared to the faintest astrophysical sources we observed with LOFAR, the unintentional electromagnetic emission from Starlink satellites is 10 million times brighter.

“This difference is like the difference between the faintest stars visible to the naked eye and the full moon. This problem is becoming increasingly serious as SpaceX launches about 40 second-generation Starlink satellites every week.”

Earth’s skies are becoming increasingly crowded, and as more and more satellites join the growing flock, this is causing increasing concerns for our night skies.

SpaceX is just one company. OneWeb has 634 satellites. Amazon plans to launch more than 3,000. China’s Space Sail Constellation is aiming for 15,000. The most obvious effect of these satellites is the visible streaks of light they leave behind in images taken at dusk.

But visible light pollution isn’t the only type of light pollution caused by satellites. A study last year showed that the constellation’s satellites emit radio waves outside the 10.7-12.7 gigahertz range used for downlink communications.

Some of these sources lie in the 150.05–153 megahertz (MHz) range used in radio astronomy. The new study analyzed data from the European LOFAR (LOW Frequency Array) network, which consists of about 20,000 radio antennas distributed across 52 locations.

They used two 1-hour observations from six central LOFAR stations and observed 97 Starlink satellites emitting radio waves in the 110–188 MHz frequency range; the emissions from the v2mini versions were significantly brighter than those from the first-generation Starlink satellites.

There are currently no rules governing the unintentional leakage of electromagnetic radiation from the constellation’s satellites. Researchers strongly recommend that such rules be implemented. While the leakage from one or a single satellite swarm is negligible, the more satellites that enter low Earth orbit, the brighter the radiation will be.

In addition, researchers are calling on Starlink to use data analysis to identify the source of unwanted electromagnetic radiation on its satellites and find a way to fix the problem before it gets even more out of control.

“Humanity is clearly approaching a turning point where we must take action to preserve the sky as a window for exploring the universe from Earth. Satellite companies have nothing to do with creating this unwanted radiation, so minimizing it should also be a priority in space sustainability policies,” says Federico Di Vruno, an engineer at the SKA observatory.

“Starlink is not the only major player in low Earth orbit, but they have a chance to set the standard here.”

Radio astronomy is not just important for space exploration. The technological advances and discoveries made for space exploration have helped develop technologies we use on Earth, from Wi-Fi and GPS to medical imaging. Undermining radio astronomy would have unforeseen consequences.

“We need support from regulatory authorities and the industry needs to come to us,” says Jessica Dempsey, CEO and Chief Scientific Officer of ASTRON. “If there is no reduction, very soon the only constellations we will see will be man-made.”

SpaceX did not immediately respond to ScienceAlert’s request for comment. The study was published in the journal Astronomy & Astrophysics.