May’s solar storm lit up night skies around the world with vibrant auroras, but it also caused chaos in orbit, as a sudden thickening of the upper atmosphere forced thousands of satellites to simultaneously maneuver to maintain their altitude.
According to a preprint paper published in the online repository arXiv on June 12, satellite and Space debris The object in low Earth orbit (space up to 1,200 miles (2,000 kilometers) above sea level) was sinking toward Earth at a rate of 590 feet (180 meters) per day. During the four-day storm .
To compensate for the loss of altitude, thousands of the spacecraft simultaneously fired their thrusters to resume their ascent — a massive maneuver that the study authors say could lead to dangerous situations. Collision Avoidance Systems There was no time to calculate the satellite’s orbital changes.
The solar storm It struck the Earth from May 7 to 10. It reached a G5 intensity, the highest level on the five-level scale used by the National Oceanic and Atmospheric Administration (NOAA) to rate the strength of solar storms. The most powerful solar storm to ever hit Earth Since 2003.
But the authors point out that the environment around Earth has changed dramatically since then: Twenty years ago, there were only a few hundred satellites orbiting the Earth; today there are thousands. The authors estimate the number of “active payloads” to be around 100 million. [low Earth orbit]10,000.
“The May 2024 geomagnetic storm was the first major one to occur in a new paradigm of LEO satellite operations dominated by small commercial satellites,” wrote study authors William Parker and Richard Linares of the Massachusetts Institute of Technology.
Solar storms are caused by large ejections of electrically charged gases ejected from the Sun. Sun Disturb Earth’s magnetic field As a result, electrically charged solar particles penetrate deep into the atmosphere, Earth’s atmosphere They interact with the molecules of air, and through that interaction, they create amazing Aurora Not only does it emit sunlight and the Southern Lights, but it also heats up and expands the atmosphere, which increases the density of the thin residual gas at the altitude where the satellite orbits. The satellite suddenly finds itself struggling against a much thicker medium and begins to lose altitude.
The new paper notes that space weather forecasts ahead of the May storm were unable to accurately predict the storm’s duration and intensity, making the satellite collision nearly impossible to predict.
“The storm caused large and unpredictable perturbations in the orbits of satellites in low Earth orbit, posing serious challenges to existing merger assessment infrastructure,” the authors wrote. “In particular, Starlink Constellation causing almost half of the satellites to become active. [low Earth orbit] “We had to maneuver immediately in response to the storm. The combination of unpredictable satellite drag and the large amount of maneuvering made it extremely difficult or impossible to identify potential conjunctions during the storm and for several days afterward.”
On the plus side, the storm cleared away some of the debris, sending defunct satellites and other debris plummeting deeper into the atmosphere: The report’s authors estimate that thousands of pieces of space junk lost several kilometers of altitude during the storm.
More powerful solar storms are expected to occur in the coming months, as the peak of the current solar cycle — an 11-year cycle in which the number of sunspots, solar flares, and eruptions waxes and wanes — is expected in late 2024 or early 2025.
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