ESA funds space weather satellite swarm to understand and combat orbital debris

Prof warns El Reg solar storms may cause cascading collisions that make some orbits unusable

The European Space Agency has funded a mission to launch a fleet of satellites that will help scientists study space weather and how it can increase debris orbiting our home world.

The project, dubbed ROARS - Revealing the Orbital and Atmospheric Responses to Solar activity – involves 26 research institutions across nine countries, including the UK, Germany, Austria, and the US.

The ROARS mission plan calls for the creation of eight microwave-oven-sized cubesats packed with sensors capable of taking measurements of Earth’s atmosphere and magnetosphere, to investigate how space weather events, such as solar flares, affect orbiting satellites.

Such weather events can change the atmosphere in near-Earth space, and thus the atmospheric drag our satellites experience, eventually causing those sats to move out of their intended orbits. As the project put it, space weather can "heat our upper atmosphere and play havoc with spacecraft trajectories."

Here's the crucial part: When sats shift, they can collide with other objects, creating debris that in turn strikes other satellites, creating a cascade of increasing debris and chaos, a situation dubbed the Kessler Syndrome. If that were to happen, with loads of bits of machinery swirling our world, it will be way more difficult to successfully operate birds in Earth's orbit, or even travel out into space from our planet in one piece.

The exponentially increasing number of satellites mean that the risks are also exponentially increasing

"Until now satellite operators were content to mitigate [satellite collision risks] through additional shielding, and extra fuel for collision avoidance," Ravindra Desai, the mission's principal investigator and assistant professor at the University of Warwick's Centre for Fusion, Space and Astrophysics in England, told The Register.

"The exponentially increasing number of satellites mean that the risks are also exponentially increasing, and more needs to be done to find a deep rooted understanding of the problem and solution as opposed to superficially treating the effects."

The key to that, Desai and his colleagues believe, lies in studying the relationship between space weather and space debris.

They therefore want the ROARS cubesats to take measurements that reveal how atmospheric densities respond to solar flares and alter satellites’ orbits. The data can then be used to model and predict how spacecraft orbits will change during space weather events, and perhaps inform space agencies and companies how to avoid collisions with other satellites or space junk.

"We also want to measure the magnetic fields and plasma properties. When solar storms hit the earth's magnetic field, they induce current systems which flow through our atmosphere and cause the aurora. These large currents also heat our atmosphere and increase satellite drag," Desai explained.

Space weather events that disrupt sats are not science fiction. During a 2022 geomagnetic storm, 40 satellites in SpaceX’s Starlink broadband-beaming constellation shifted not just out of position but into Earth's upper atmosphere, where they burned up. As the spacecraft were lost, they didn't add to the 50,000-plus fragments of debris tracked in orbit by the US Space Force's Space Surveillance Network. Millions of other tiny pieces of space trash that also pose a collision risk cannot be monitored effectively.

The risk all the debris creates is substantial.

"We are approaching a tipping point where an increasing number of collisions are producing more debris which in turn produce even more collisions," Desai told us. "This exponential increase in debris is known as the Kessler Syndrome and scientists are worried it could produce so much debris, it could render Earth's orbit unusable [for satellites]. We depend on everything for satellites nowadays, from mobile phones, GPS navigation to the financial system and cyber security."

ESA has provided funding totaling £86 million ($100 million) for its "Innovative Mission Concepts Enabled by Swarms of CubeSats" and has selected seven designs for the mission.

To avoid contributing to the space junk problem, the ROAR satellites will be safely deorbited within five years when they reach the end of their missions. Desai told us the project will have to complete an in-orbit demonstration in 2026 if it is to become a full mission in 2029. ®

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