Starlink satellite paths observed from space
Don Pettit/NASA
The proliferation of satellites in orbit is accelerating rapidly, yet their vulnerability to solar storms remains poorly understood. This issue is expected to intensify.
Since May 2019, SpaceX has deployed over 10,000 satellites as part of its Starlink internet megaconstellation, with approximately 1,000 currently re-entering Earth’s atmosphere at a rate of one or two daily. These satellites form a vast network surrounding the Earth, which suggests that solar and related geomagnetic storms could impact at least some satellites at any given time.
To assess the implications of these storms on Starlink, Kang Eun Joo and researchers at the University of California, Irvine, analyzed publicly available satellite tracking data collected during the solar storm of May 2024.
The findings indicated that during the storm’s peak, Starlink satellites on the sun-facing side experienced an altitude reduction of up to half a kilometer. While this drop is minor compared to their 550-kilometer orbit, it is significant because solar radiation can generate atmospheric drag on the satellites.
Satellites in other locations, particularly those near the Earth’s poles where the magnetic field attracts more solar particles, and those over the South Atlantic Anomaly, where the magnetic field has weakened, also experienced substantial effects.
According to the data reviewed by the research team, an unusual phenomenon occurred among the constellations. “When one satellite descends, neighboring satellites must adjust accordingly,” Kang explained, utilizing onboard ion thrusters to recalibrate the affected satellites. This is necessary since the satellites communicate via line-of-sight lasers to maintain the network, which creates a cascading effect as adjacent satellites follow suit. “It’s like a wave,” remarked Sangeeta Abdu Jyoti, another researcher at UC Irvine.
This could lead to challenges for other satellites maneuvering around the Starlink constellation to prevent collisions. “Unpredictable paths heighten collision risks,” Abdu Jyoti cautioned.
Additional publicly accessible data also reveals the repercussions of solar storms. Some Starlink users utilize an online service called RIPE Atlas to monitor their connection status. By analyzing this information, Kang and her team noted that satellites experienced disruptions and reported network outages during the May 2024 storm. “Packet loss surged immediately,” Kang stated, resulting in data failing to reach its intended targets.
This study emphasizes the challenges faced by satellite constellations such as Starlink, as well as those in development like Amazon’s Project Kuiper and various projects in China, due to solar activity jeopardizing communication and potentially leading to drastic positional changes that could result in collisions with other satellites.
In February 2022, a significant solar storm caused 40 newly launched Starlink satellites to return to the atmosphere, where they incinerated. Recent studies have also indicated that heightened solar activity is accelerating the decline of certain Starlink satellites.
The May 2024 solar storm was roughly three times weaker than the Carrington event of 1859—the strongest solar storm on record. Such records are likely to be repeated, potentially creating significant challenges for satellite operators. “If an exceptionally strong storm occurs, the situation will worsen,” Abdu Jyoti said. “But the extent of that worsening remains uncertain.”
For now, I hope to have adequate preparation time. The May 2024 storm happened at the peak of the sun’s 22-year activity cycle. A powerful storm could strike at any moment, with a higher likelihood expected in the 2040s when solar activity intensifies again. By that time, it’s anticipated that tens of thousands, if not hundreds of thousands, more satellites will be in orbit compared to the current approximate count of 13,000. “The more satellites you have, the greater the issue,” stated Scott Shambaugh, founder of Leonid Space, a US company tracking the impact of space weather on satellites.
“Currently, we lack reliable predictive models to assess how solar storms impact drag over short timescales,” Shambaugh explained. “Consequently, satellites may not be where anticipated for hours or days following a storm.”
Matthew Owens identified another area needing further understanding: substorms—minor fluctuations in the atmosphere caused by solar heating that disproportionately affect satellites in varied orbits, according to researchers from Britain’s University of Reading. “Geomagnetic storms consist of numerous substorms,” he noted, “but these are extraordinarily challenging to forecast.”
Satellite constellations like Starlink provide a unique perspective on this activity, effectively serving as a massive research network in orbit around Earth. “These satellites may very well be our first data probes for analyzing local variations in atmospheric drag,” Abdu Jyoti concluded.
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Source: www.newscientist.com
