Starlink Satellites Emitting Radio Signals That May Disrupt Astronomy

Astronomers have raised concerns that SpaceX’s Starlink satellites emit radio waves that may jeopardize their ability to observe and comprehend the early universe.

With thousands of Starlink satellites in orbit offering worldwide internet coverage, astronomers worry that radio emissions from these satellites could interfere with sensitive telescopes monitoring distant and faint radio waves. Although SpaceX has collaborated with astronomers to minimize this disruption by disabling transmission beams while passing over significant telescopes, these measures seem insufficient.

Steven Tingay from Curtin University, Australia, along with his team, is currently tracking signals from nearly 2,000 Starlink satellites using prototype telescopes at the Square Kilometer Array-low Observatory (SKA-low). This future network of over 100,000 interconnected telescopes is designed to investigate the early universe, but researchers have found that Starlink signals could jeopardize their goals by affecting a third of the data gathered at numerous frequencies.

Additionally, they found that the satellites transmit signals in two frequency bands protected for radio astronomy by the International Telecommunications Union (ITU), which should not be utilized for Starlink transmissions. Yet, these satellite emissions are deemed unintentional. The leaked signals are 10,000 times stronger than the faint radio emissions from the neutral hydrogen clouds that existed when the first stars began to form, and which astronomers wish to study to decode the early universe.

“The signal strength from these unintended emissions can rival some of the brightest natural radio sources in the sky,” Tingay explains. “It’s akin to taking the strongest sauces in the sky, adding even more artificial ones, and causing significant interference, especially in experiments that target super sensitivity.”

Tingay suggests that the emissions likely arise from onboard electronics inadvertently transmitting signals through satellite antennas. He notes that while such leaks are not technically illegal, as ITU regulations only cover intentional emissions, the discourse about how to regulate these types of emissions is starting at the ITU, which has withheld comment.

Dylan Grigg, another researcher from Curtin University, emphasizes, “The optimal approach to mitigate these unintended emissions is for satellites to either reduce or eliminate them. From the operator’s perspective, it’s beneficial that there are existing mitigation strategies in satellites, which SpaceX has already implemented for optical astronomy.” Starlink has adjusted its satellites to minimize light reflection to reduce visual interference.

A spokesperson for SKA-LOW remarked, “These findings align with our previous studies, but additional research is necessary to fully grasp the impact on low-frequency observations.”

Grigg and Tingay have shared their findings with SpaceX, stating that the company is open to discussions on strategies to decrease emissions. SpaceX has not commented on the matter.

If SpaceX cannot devise a solution, researchers may need to introduce algorithmic strategies to filter out contaminated radio waves. However, Tingay pointed out that such methods are still in their early development phases and might require more computational resources than are currently needed for basic processing of the astronomical signals of interest.