Latest solar superstorm blinds systems to avoid satellites crashing into space | Science

The largest geomagnetic storm in more than 20 years left a very unusual natural spectacle between May 10 and 12 — the northern lights in countries such as Spain — and caused an artificial phenomenon that had never been seen before. According to preliminary research by American scientists from the Massachusetts Institute of Technology (MIT), the arrival of an intense gust of solar wind to Earth caused half of all active satellites to migrate for the first time. With the Sun in its most active phase, it is quite possible that similar storms will recur this year or next.

The authors of the investigation warn that such a number of unexpected movements disabled, during the days of the hurricane and in the days that followed, safety systems designed to prevent collisions in low Earth orbit. The region of space that surrounds our planet, at an altitude of up to 1,000 kilometers, is home to two space stations where Western astronauts and Chinese taikonauts permanently live, as well as numerous scientific observation, navigation and telecommunications satellites. Among them are more than 6,200 Starlink satellites from Elon Musk’s SpaceX, designed to provide global high-speed Internet coverage without cables.

The rapid proliferation of these types of devices is a huge change in the space around Earth since the last solar superstorm in October 2003, when there were only 850 active satellites compared to the current 10,000. Their mass launch began in 2019, and they have been changing the appearance of the night sky to the naked eye ever since; astronomers have also warned that they are interfering with important research such as detecting dangerous asteroids heading toward Earth.

Now, mega-constellations of satellites have led to an unprecedented phenomenon that space-tracking systems are not prepared for, according to a new study just accepted for publication in the journal. Spacecraft and Rockets Magazine. William E. Parker, lead author of the study, explains to EL PAÍS that “when unexpected events occur, such as a geomagnetic storm that pulls thousands of satellites (towards Earth), it is almost impossible for us to predict what the future positions of the satellites will be. This leaves us blind to potential short-term collisions. It’s like driving on the wrong side of the road with your eyes closed.”

Parker explains in his paper that when solar wind from a geomagnetic storm reaches Earth, in addition to the charged particles interacting with the magnetosphere and generating the auroras, another phenomenon occurs that is not visible or well known: the high parts of the atmosphere heat up and swell up like a soufflé. This increases friction on the satellites; as they slow down, they lose altitude (up to almost 200 meters per day during the last superstorm).

That’s why May’s solar storm caused widespread and rather sharp drops — compared to normal rates — in low-orbiting satellites. Parker and his advisor at MIT’s Department of Aeronautics and Astronautics, Richard Linares, observed this approach to Earth using publicly available tracking data from all 10,000 active satellites provided by the U.S. Space Force. Their analysis revealed something that had never been seen before: About 5,000 of the satellites swept up by the solar storm began to rise. Most of these unexpected maneuvers, Parker and Linares explained in their paper, corresponded to satellites in the Starlink constellation, which are capable of moving autonomously until they return to normal orbit. So the satellites decided to maneuver on their own after the disturbance occurred.

SpaceX boasts this capability, which allows it to remain operational in the event of an incident. But the authors of the new study point out that so many unplanned movements over a few hours have undermined predictions for the next week of close encounters — less than 100 meters away — between the satellites and other objects in orbit, including small pieces of space junk measuring 10 centimeters or larger that travel at nearly 30,000 kilometers per hour. After the storm passed and the mass migration occurred, Parker and Linares explain that the spacecraft’s collision avoidance systems had to be restarted on the satellites’ new anniversaries to recalculate the probabilities of encounters in the days that followed.

David Galadi, a researcher at the University of Cordoba who studies the impact of mega-constellations on astronomy, points out a worrying fact: “Since SpaceX started launching Starlink satellites, ESA has doubled the number of collision avoidance maneuvers.” To minimize the risks, these maneuvers are carried out when the probability of a collision is estimated to be more than 1 in 10,000. But Galadi warns against panicking, and remembers that collisions, although they have already happened, are still very unlikely in low Earth orbit.

For Alejandro Sánchez, an astrophysicist at the Complutense University of Madrid, what is more worrying than the current collision risk is the lack of regulation. “We need more research to be able to quantify the risk, because there are people up there in the space stations. It’s happening too fast and without planning,” says the scientist, who decries the fact that no operator launching a satellite is required to equip it with a collision avoidance system; and that the agencies that authorize launches also do not require them to comply with general space safety regulations. “Those who do something, like SpaceX, do it themselves to protect their devices and their business,” concludes Sánchez.

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