Satellites belonging to Elon Musk's constellation inexplicably malfunctioning: Link between failures and magnetic disturbances explained.
Title: Elon Musk's Starlink Satellites: Falling Rate-Why and the Role of Magnetic Storms
Elon Musk's SpaceX Starlink satellites are experiencing an uptick in falls, and a group of physicists from NASA's Goddard Space Flight Center have uncovered some fascinating insights.
Over the years, the number of fallen Starlinks has been gradually increasing. While just two satellites fell in 2020, the count reached 78 in 2021, 99 in 2022, and 88 in 2023. However, the biggest spike occurred last year, with a staggering 316 satellites re-entering Earth's atmosphere. In total, the constellation has lost 583 objects.
Sadly, there are no statistics available for this year yet. As of the beginning of 2023, there were 7086 Starlinks in orbit, with the number rapidly increasing to 8873 satellites, of which only 7769 are operational. Despite the vast number of operational Starlinks, approximately every 15th satellite is lost, which is concerning.
Researchers found that this trend correlates with solar activity, particularly intense solar activity during the current solar cycle.
- We've proven that the intense solar activity of the current solar cycle has already significantly affected the re-entries of Starlink into the atmosphere. This is an exciting time for studying orbital drag, as the number of satellites in low Earth orbit during the peak of solar activity is the highest in human history, - the study reveals.
Launches of Starlink began during the solar activity minimum in 2019, and 2024 was the year of maximum Sun. Solar activity follows an 11-year cycle, and when many sunspots appear on the star, powerful explosions occur, leading to solar flares. Solar material, including towards Earth, escapes through so-called coronal holes, causing magnetic storms on Earth.
When the Earth is hit by solar plasma and a magnetic storm ensues, it triggers another effect: heating of the upper atmosphere. Although we can't breathe at the cosmic heights where this heating occurs (tens of air atoms per cubic meter), satellites—especially those in low Earth orbit—are sensitive to the resistance of this thin air layer. When the atmosphere heats up, it expands. Satellites begin to experience greater resistance to their flight, drift off orbit, and eventually fall.
Satellites like those in the Starlink constellation need to maintain connectivity, so their orbits are typically low (200-600 km, similar to the International Space Station). The lifespan of these satellites is roughly five years on such orbits. Although the ISS lasts longer with regular orbit correction, satellites without self- propulsion will still fall within five years due to solar activity.
While the phenomenon is generally understood, there's still a lot we don't know. For instance, 70% of satellites fell not during strong but during moderate and weak magnetic storms. Weaker storms, being longer, may gradually erode the satellite's orbit, leading to an inevitable re-entry.
The authors of the article express their enthusiasm for this "laboratory" provided by Elon Musk through his Starlink launches. They find it intriguing to witness the satellites falling. Musk might not share their fascination.
Fun Fact: Did you know that during the solar maximum of 2000, a record of 22 solar flares in a single day was set? That's more than double the previous record!
[1] Enrichment Insight: Solar flares and coronal mass ejections (CMEs) can lead to geomagnetic storms, which increase the energy and ionization in Earth's upper atmosphere. This can enhance the atmospheric drag on satellites, particularly those in low Earth orbit like the Starlink satellites. [2] Operational Challenges: The unpredictability of solar storms and the subsequent increase in satellite re-entry rates pose operational challenges for managing satellite constellations like Starlink. It requires more precise predictions and adaptive strategies to mitigate losses and ensure the satellites reach their operational orbits safely. [3] Orbital Decay and Re-entry: The increased drag from geomagnetic storms accelerates the orbital decay of satellites, causing them to re-enter the atmosphere more quickly than anticipated. This can lead to satellites entering the atmosphere before they reach their intended operational altitude or before they can adjust their orbits using onboard thrusters. [4] Overall: The combination of solar activity, geomagnetic storms, and increased atmospheric drag is a significant factor in the increased rate of satellite falls from the Starlink constellation.
- The increased rate of Starlink satellite re-entries can be linked to the current solar cycle, with researchers discovering that intense solar activity correlates with an uptick in falls.
- Intriguingly, the study suggests that weaker, longer magnetic storms, rather than strong ones, may contribute to the erosion of satellite orbits, leading to a higher number of falling Starlink satellites.
