Eruptions from the sun are shortening the lives of satellites in Earth orbit, particularly large constellations like SpaceX鈥檚 Starlink 鈥� which could be both beneficial and a cause for concern.
The sun goes through an 11-year cycle of activity, peaking with a period known as solar maximum, which most recently occurred in late 2024. During these periods, increased eruptions from the sun can create geomagnetic storms that heat our planet鈥檚 atmosphere, causing it to swell outwards in size and increasing drag on satellites.
Now, at NASA鈥檚 Goddard Space Flight Center in Maryland and his colleagues have investigated how much of an effect this was having on Starlink. 鈥淲e found that when we have geomagnetic storms, satellites re-enter faster than expected [without solar activity],鈥� he says. During solar maximum, the lifetime of a satellite could be reduced by up to 10 days, the researchers say.
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This effect is only becoming apparent now because of a boom in satellite launches, particularly by SpaceX. There are more than 7000 Starlink satellites orbiting Earth, providing a space internet service on the ground. New satellites are constantly being added to the constellation, with launches taking place almost every week. SpaceX plans to have maybe more than 30,000 orbiting satellites in the future.
But there are also several re-entries each week, and the constellation is constantly replenished. 鈥淚t鈥檚 the first time in history we have so many satellites re-entering at the same time,鈥� says Oliveira. Between 2020 and 2024, 523 Starlink satellites were tracked re-entering our atmosphere, where they are designed to entirely burn up. 鈥淚n a few years, we will have satellites re-entering every day,鈥� says Oliveira.
Some Starlink satellites are purposefully lowered into the atmosphere at the end of their life, while others fall naturally under atmospheric drag when they fail. Oliveira found that during the most severe recent geomagnetic events, when 37 Starlink satellites re-entered, satellites orbiting below 300 kilometres re-entered after around five days, down from more than 15 days.
鈥淭his is the first solar maximum that we鈥檝e had in the mega constellation era,鈥� says at the University of Regina in Canada. 鈥淪o it is important to do these measurements.鈥�
at the University of Birmingham, UK, says this effect could benefit satellite operators like SpaceX by removing dead satellites from orbit more quickly that could otherwise pose a danger to other satellites. 鈥淚t鈥檚 speeding up that process,鈥� he says. However, it could limit our ability to operate satellites in orbits below 400 kilometres, known as very low Earth orbit. 鈥淚t shows that could be challenging,鈥� he says.
There is also a possibility that quicker re-entries could make it less likely that the satellites will completely burn up in Earth鈥檚 atmosphere, says Oliveira. 鈥淵ou could have a chance of an object reaching the ground,鈥� he says.
In August 2024, a 2.5 kilogram piece of a Starlink satellite was found on a farm in Saskatchewan, Canada, the only known instance of any piece of Starlink satellite surviving re-entry . Lawler, who lives in Saskatchewan, says she worries that more satellite debris might have made it to the ground elsewhere.
鈥淭his is the easiest place in the world to find Starlink debris,鈥� she says, because the land is so flat and open, and it is under the densest part of satellite paths in the constellation. 鈥淚f we found one [piece] here, how many did we miss?鈥�
SpaceX didn鈥檛 respond to a request for comment.
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