This post was originally published on here
Studies have found solar storms can take out satellites’ navigational and communications systems, which enable them to manoeuvre away from each other and prevent collisions.
Even a single collision between satellites may develop into a cascade that could threaten orbits for decades, according to previous research.
As the number of satellites in orbit rapidly increases in this era of mega-constellations such as SpaceX Starlink probes, the chances of satellites colliding grow dramatically.
However, there hasn’t been a proven way to measure exactly how stressed the Earth’s orbital environment has become, said researchers, including those from Princeton University.
This measure estimates how long it may take for a pile-up to happen in low Earth orbit
Now, scientists have developed a “Crash Clock” to quantify the fragility of satellites in low Earth orbit.
This measure estimates how long it may take for a pile-up to happen in low Earth orbit if satellites suddenly stopped avoiding each other, which would be likely in the event of a devastating solar storm.
“It is a measure, in part, of the degree to which the orbital environment is a house of cards,” researchers write in the yet-to-be peer-reviewed study.
Before companies and governments began launching satellite swarms, a collision cascade may have taken about four months to develop after an event like a solar storm.
But the enormous increase in the number of satellites in orbit since 2018 has brought down the number of days for a collision to under three days, the new study warns.
This represents a 30pc probability of one or more satellite collisions happening during 24-hour period of the probes remaining non-manoeuvrable, scientists explain.
Researchers said this probability is within the “caution region”.
Further increase in orbital traffic could raise collision risk into the “danger region”, implying a 50pc chance of at least one collision within 24 hours, they said.
The research takes into consideration the number of collision avoidance manoeuvres performed by satellites each year.
Citing a SpaceX report, scientists noted Starlink satellites make about 40 such manoeuvres per satellite per year “or one collision avoidance manoeuvre every 1.8 minutes across the whole mega-constellation”.
