Solar flares are no joke, especially when your society depends on wireless communication.
Credit: NASA
The Science and Technology Facilities Council (STFC), a UK government research body, has published the fourth edition of its report, “Summary of Space Weather Worst-Case Environments.” As the name implies, it’s a banger of a read.
The main takeaway is that many of humanity’s most critical technologies are more vulnerable to space weather than people believe and, more importantly, are becoming more vulnerable by the year.
The report focuses on “worst-case” scenarios, which basically means solar flare-ups that could plausibly happen every 100 to 200 years or so. Events with that kind of frequency have a meaningful chance of happening in any given year—and, for the record, they can still happen even if a similar one occurred relatively recently.
The STFC’s report defines space weather as “disturbances of the upper atmosphere and near-Earth space that disrupt a wide range of technological systems—and, in a few cases, pose a direct threat to human health.” It shows that plausibly large space weather events could knock out satellites, crucially including GPS satellites, and terrestrial power grids as well.
This figure breaks down space weather, as the STFC sees it.
Credit: Science and Technology Facilities Council
These events could last up to two weeks, but they could do more than just temporarily disrupt communications; they could also damage infrastructure, requiring lengthy repairs and prolonging the downtime of critical global systems. This includes services that will be directly downed, like GPS, and indirectly, like flights that rely on GPS for safe navigation.
The STFC sums this up by claiming that it is “highly likely” that global system failures will cascade, causing further problems that are “fundamentally difficult to predict.”
Blown transformers and even regional blackouts could be the least of our worries. The real danger, and one that is not difficult to predict, is the destruction of most or all satellites in space at the time of the event. Constellations (and mega-constellations) are becoming less and less fault-tolerant as they become more tightly packed in the sky.
In December, we reported that a disruption in satellite control wouldn’t need to last long to cause a catastrophic collision, and that every new satellite added to low Earth orbit brings the overall status quo closer to disaster.
2025 saw more than 4000 new satellites enter orbit.
Credit: ESA
SpaceX has pushed its Stargaze system to mitigate these fears, arguing that it will be able to track and coordinate thousands, and eventually tens of thousands, more objects in LEO, but such systems remain partially vulnerable to space weather.
Now, SpaceX and others will point out that, in the event of solar weather that knocks out navigation, their satellites are designed to passively drift down into the atmosphere and burn up. That’s what happened in 2022, when a geomagnetic storm hit some recently-launched Starlink satellites, destroying 40 units. That seems like a win, on the face of it, but this report details the possible impacts of storms much worse than the one seen in 2022.
Finally, the report examines the dangers for crewed space missions, though NASA and its astronaut program have largely resigned themselves to the inability to fully protect crews from highly unlikely events.
For the foreseeable future, astronauts will have to simply plan their schedules for periods of low predicted solar activity and hope for the best. The rest of us, who are overall safer on the ground, can and should demand better.
