As the number of satellites in low Earth orbit (LEO) continues to soar, SpaceX’s Starlink constellation is grappling with an escalating risk of collisions, leading to an unprecedented surge in avoidance maneuvers. Furthermore, a study published in the Astronomy & Astrophysics journal has uncovered unintended electromagnetic radiation emitted by Starlink satellites, raising concerns about its impact on astronomical research.
In a recent filing with the Federal Communications Commission (FCC), SpaceX disclosed that its orbital communication satellites performed over 25,000 avoidance maneuvers between December 1, 2022, and May 21, 2023. The company’s threshold for initiating maneuvers is “an order of magnitude” more stringent than the industry standard. SpaceX’s satellites are moved when the probability of a collision exceeds 1 in 100,000, while NASA and other industry players typically employ a threshold of 1 in 10,000.
The doubling of avoidance maneuvers compared to the previous reporting period directly correlates with the growth of the Starlink constellation. SpaceX added an additional 457 satellites to orbit during the most recent reporting period, further contributing to the congestion in LEO.
Of the 25,000 avoidance maneuvers, more than 1,300 were performed specifically to evade debris generated from Russia’s anti-satellite weapon demonstration test in November 2021. Although only 9% of the debris from that test remains in orbit, it posed the most significant risk to Starlink satellites, as indicated in the filing.
SpaceX’s Starlink project is not the sole contender aiming to establish a megaconstellation in space. With numerous companies pursuing similar ventures, it is projected that tens of thousands more objects will populate Earth’s orbit by the end of the decade, exacerbating concerns about collisions and sustainability.
Coinciding with SpaceX’s filing, the study published in the Astronomy & Astrophysics journal shed light on unintended electromagnetic radiation emitted by Starlink satellites, distinct from the signals already monitored by astronomers from communication satellites. Researchers employed a sensitive Low Frequency Array telescope to detect radiation emissions from 68 Starlink satellites and conducted simulations to understand the cumulative effect of such radiation.
“Our simulations show that the larger the constellation, the more important this effect becomes as the radiation from all the satellites adds up,” cautioned Benjamin Winkel, a co-author of the study from Germany’s Max Planck Institute for Radio Astronomy. Winkel further expressed concern over the absence of clear regulations protecting radio astronomy bands from unintended radiation.
The study’s lead author, Federico Di Vruno, who serves as the co-director of the International Astronomical Union Centre for the Protection of the Dark and Quiet Sky, is in close contact with SpaceX. The company has already introduced modifications to the next generation of Starlink satellites in an effort to mitigate the unintended emissions, as confirmed in a press release accompanying the study.
As the number of satellites in orbit continues to escalate, urgent attention from the space industry and regulatory bodies is necessary to address the challenges arising from congestion and potential interference with scientific research. Striking a balance between the rapid expansion of satellite constellations and ensuring the long-term sustainability of space activities is crucial to safeguarding the future of low Earth orbit.