Volatile solar activity rapidly increases the amount of space debris falling to Earth, such as old satellites and rocket stages, creating challenging-to-predict hazards for space launches, according to new research from India’s Vikram Sarabhai Space Center.
Low Earth orbit, the region 400 to 2,000 kilometers above the surface, where essential satellites governing GPS and communications infrastructure reside, is also home to a tremendous and growing amount of space debris, which must be carefully monitored to ensure launch safety for space missions.
According to a new paper published in Frontiers in Astronomy and Space Sciences, solar activity is increasing the instability of this floating trash, potentially triggering a domino effect that threatens multiple satellites.
Monitoring Space Debris
Capturing space debris and removing it from orbit remains a nascent subfield within the broader space economy, making monitoring essential for safe launches.
“Here we show that space debris around Earth loses altitude much faster when the Sun is more active,” said co-author Ayisha M. Ashruf. “For the first time, we find that once solar activity passes a certain level, this loss of altitude happens noticeably more quickly. This observation is expected to be key for planning sustainable space operations in the future.”
Solar activity follows an 11-year cycle, during which the Sun passes through low- to high-intensity phases that are known to produce violent space weather. Previous work has focused on how space weather can cause electrical disruptions that can be dangerous to essential satellite infrastructure, damaging its onboard electrical systems. Yet in this study, an entirely different problem arises: the effect of space weather on floating space junk physically crashing into active satellites, creating unexpected obstacles to new launches.
Solar Particles
In more active periods, solar flares and coronal mass ejections can hurl heavy doses of UV radiation and charged particles, such as helium nuclei and heavy ions, toward the Earth. This has the effect of heating our planet’s thermosphere and increasing drag on near-Earth objects as atmospheric density rises. Under that increased resistance, objects begin to slow their orbits and fall at much greater rates.
For their research, the Vikram Sarabhai team reviewed 36 years of historical data covering the 22nd through 24th solar cycles. Over that period, they tracked 17 space junk objects at altitudes ranging from 600 to 800 kilometers through their 90- to 120-minute orbits, until they eventually burned up in the atmosphere.
These inanimate objects were completely at the mercy of their thermosphere density-drive orbital decay as they fell out of the sky, as they lacked the ability to alter their own orbits as active satellites do. According to the researchers, space junk is an excellent way to study the relationship between atmospheric drag and solar activity.
Space Debris Danger Zone
In their analysis, the researchers identified a crucial threshold at which space junk begins to fall much more rapidly, around two-thirds of the way through the sunspot cycle.
“This threshold doesn’t seem to be tied to a fixed value of solar radiation, but rather to how close the Sun is to its peak activity,” Ashram said. “Around this point, the Sun produces more intense EUV radiation, which may be driven by changes in solar processes that become stronger near the peak.”
The researchers say their work will be crucial to future space missions, as planners will now have to recognize and mitigate the increased dangers of launching during solar activity above that two-thirds threshold. Additionally, planners should consider the effect of solar activity on thermospheric drag when planning mission length and fuel loads to ensure successful completion.
They were also quick to note that this work highlights how meaningful even historical space objects can be to modern research, with some of the space debris they tracked having origins with launches all the way back in the 1960s.
The paper, “Characterizing Solar Cycle Influence on Long-Term Orbital Deterioration of Low-Earth Orbiting Space Debris,” appeared in Frontiers in Astronomy and Space Sciences on May 6, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.