The new solar cycle could be difficult for satellites around the Earth. Since last fall, scientists have noticed an increase in solar activity, which literally “pushes” satellites from orbits into the atmosphere, writes Space.com.
In late 2021, European Space Agency operators noticed that Swarm satellites, which measure the Earth’s magnetic field, began to lose altitude up to 10 times faster than before.
“In the last five, six years, the satellites were sinking about two and a half kilometers a year. But since December last year, they have been virtually diving. The sink rate between December and April has been 20 kilometers per year,” said a researcher at the European Space Agency.
The change coincided with the beginning of a new solar cycle that lasts 11 years. The new cycle ended in December 2019 and was marked by a minimum of solar activity. Instead, scientists are now seeing more solar wind, sunspots, solar flares, and rising coronal mass emissions. This could not but affect the upper atmosphere.
Spacecraft in orbit around the Earth are always resisted by the upper atmosphere, which slows them down and eventually causes them to fall to the planet, burning in the atmosphere. Because of this, the ISS and satellites that have engines, from time to time perform maneuvers to keep at the desired height. This phenomenon also clears the orbit of space debris.
According to scientists, the interaction of the solar wind with the upper atmosphere raises up denser air, which creates greater resistance for satellites.
“It’s almost like running with the wind against you. It’s harder, it’s drag — so it slows the satellites down, and when they slow down, they sink,” explains the scientist.
Swarm satellites have been rescued, but they are not the only ones affected by the sunny weather. In February, SpaceX lost 40 new satellites. After launch, they did not have time to bring to a safe height, and a solar storm knocked them to Earth.
“The solar activity is a lot higher than the official forecast suggested. In fact, the current activity is already quite close to the peak level that was forecasted for this solar cycle, and we are still two to three years away from the solar maximum., says a researcher from the University of Southampton.
The rapid growth of solar activity will force spacecraft in orbit to start engines more often to stay at the right height. It will also reduce the lifespan of simpler and cheaper satellites that have no way to climb. At the same time, it will clear the orbit of space debris, which is already threatening the security of satellite services.