SpaceX and Astronomers Collaborate to Safeguard Radio Observations

SpaceX has teamed up with astronomers to develop an innovative automated data-sharing system designed to protect radio telescopes from interference caused by satellites in low Earth orbit (LEO). This collaboration aims to mitigate the disruptive effects that large satellite constellations, such as SpaceX’s own Starlink, have on sensitive astronomical observations.

The growing number of satellites in orbit provides high-speed internet to underserved areas, but they also present a challenge for radio astronomy. These telescopes, which are crucial for detecting faint radio waves from distant cosmic phenomena such as black holes and neutron stars, are increasingly affected by the interference produced by satellite signals. Astronomers working on the Square Kilometre Array Observatory (SKAO), located in Australia and South Africa, have raised concerns that LEO satellite interference could obscure signals that might indicate extraterrestrial life and drown out radiation from the most distant galaxies.

### Innovative Solution Developed

A team of researchers from the U.S. National Radio Astronomy Observatory (NRAO) has spent three years crafting a solution to this problem. Partnering with SpaceX, they have created a complex data-sharing system that communicates real-time information about telescope observations, including the specific frequencies being used. When Starlink satellites pass over these telescopes, the system instructs them to redirect their beams or mute their electronic signals.

Chris De Pree, deputy spectrum manager at the NRAO, emphasized the system’s effectiveness, stating, “The good news is that it’s autonomous on both sides. We are sending information in real time to SpaceX about what the telescope is doing, their system digests it and issues commands to the satellites that are approaching the telescope.”

The system comprises two main components: the Operational Data Sharing (ODS) system, which relays observing schedules to Starlink, and the Starlink Telescope Boresight Avoidance algorithm, which directs satellites to adjust their beams accordingly. Since August 2024, this system has been successfully tested at the NRAO’s Very Large Array (VLA) in New Mexico, with plans for further testing at additional facilities including the Very Long Baseline Array and the Green Bank Telescope in West Virginia.

### Addressing Growing Concerns

The VLA, located near Socorro, New Mexico, consists of 28 radio antennas, each measuring 82 feet (25 meters) in width. Built in the 1970s, this array has played a significant role in advancing our understanding of black holes, young stars, and the dynamics of the Milky Way galaxy. However, since the launch of the first Starlink satellites in 2019, astronomers have recognized that the proliferation of satellite megaconstellations could severely hinder their ability to study the universe.

“For decades, radio astronomers have been building telescopes at remote sites to avoid radio frequency interference,” De Pree noted. “With satellite constellations, there are now potentially thousands of sources of radio frequency interference directly above the telescopes.”

Cosmic radio waves, which traverse millions of light-years, are significantly weaker than the signals used for terrestrial broadcasting and communication. As a result, sensitive radio telescopes typically operate within radio-quiet zones, where broadcasting devices are prohibited. Unfortunately, no regulations prevent satellites from flying over these areas. De Pree pointed out that hundreds of satellites currently pass over the VLA each day, stating, “Nowhere is remote anymore.”

The situation is expected to worsen as satellite numbers continue to rise. The launch of the Starlink constellation has contributed to an increase from approximately 3,000 satellites in orbit in 2019 to over 8,000 operational spacecraft today. SpaceX plans to expand its Starlink fleet to more than 40,000 satellites over the next decade, while other companies, including Amazon’s Project Kuiper and Chinese initiatives like Spacesail and Guowang, are also deploying their satellite fleets. By 2030, it is estimated that around 100,000 satellites could be orbiting Earth, leading to thousands of disruptions in radio astronomy observations.

### Future of Astronomy and Satellite Coexistence

Recognizing the potential impact of these developments, the NRAO team initiated discussions with SpaceX in 2021 to explore solutions. De Pree highlighted the sensitivity of radio telescope electronics, explaining, “They weren’t developed to handle such strong signals [as the satellites produce]. It’s as if somebody is yelling at you.” This disruption can affect not only the specific frequency bands used by satellites but also a broader region of the radio spectrum.

Historically, the International Telecommunication Union set aside specific portions of the radio spectrum for radio astronomy in the 1950s. However, satellite operators have increasingly encroached on this reserved spectrum. Astronomers continuously seek to capture emissions from distant cosmic sources that often fall outside these protected bands. De Pree noted, “The challenge to radio astronomy is that a lot of these spectrum regions that used to be pretty quiet in the past are now being filled with transmissions.”

De Pree believes that the newly developed system could be adapted for use by other major radio telescopes worldwide. He hopes that not only other observatories but also various satellite operators will embrace this technology, paving the way for a peaceful coexistence between radio astronomy and internet-beaming satellite constellations.