The aurora is the light emitted by upper atmospheric particles as they interact with energized particles from the magnetosphere. The aurora borealis, otherwise known as the northern or southern lights, is the light emitted by upper atmospheric particles as they interact with charged particles from the magnetosphere.
It is a stunning and otherworldly event that people living in high latitudes can often experience. In Cree and Ojibwe teachings, the Northern Lights are ancestral spirits who remain and communicate from heaven.
For scientists, the aurora borealis is an infinitely complex amalgamation of ionospheric dynamics, a manifestation of the Earth’s internal connection with the Sun. This is a risk factor for the industry.
Starlink destruction event
In February 2022, SpaceX launched 49 Starlink internet satellites into low Earth orbit (LEO). This was SpaceX’s 36th Starlink launch, and they expected it to go off without a hitch, just like the 35 before it.
On the day of launch, Earth was hit by a coronal mass ejection a large explosion of plasma ejected from the Sun. It caused a geomagnetic storm in the atmosphere at an altitude of about 100 to 500 kilometers, which is the target range for Starlink.
This event injected a huge amount of electromagnetic energy directly into the Earth’s upper atmosphere. It produced beautiful auroras, but the energy also increased the density of the air. Higher air density is usually not a big problem for LEO satellites, as it is already extremely low at normal operating altitudes (above 400 kilometers).
Starlink was originally launched to an altitude of 210 kilometers. This is much closer to Earth, with an exponentially higher air density. 38 of these 49 initial launch satellites were subsequently lost due to atmospheric drag from the dense atmosphere pulling them back to Earth.
The surprising solar cycle
The sun goes through a cycle an 11-year cycle to be exact from which its activity periodically increases and decreases. At the peak of the cycle, we see more sunspots, more radiation emitted, and more solar flares on the solar surface.
In the previous cycle, which ended in 2019 (the 24th monitored cycle since 1755), there were 927 storms that were only classified as mild or weak an average of one every five days.
We’re currently four years into solar cycle 25, but this one has already proven to be surprising. The maximum activity of the 25th cycle was supposed to occur in 2025, but solar activity has already surpassed it. This means we’ve seen more geomagnetic storms, more aurora displays (and at lower latitudes than usual), and potentially more dangerous conditions for LEO satellites.
Space weather an invisible force of nature
If geomagnetic storms are so common, why don’t they cause more problems? The reality is that yes, but the consequences are much less obvious than with satellites burning up in the atmosphere.
For example, when space weather energy enters Earth’s upper atmosphere, the composition of the ionosphere changes and the air thickens. High-frequency or “shortwave” radio communications depend on a predictable ionosphere for long-range transmission.
Geomagnetic storms that affect the composition of the ionosphere can cause radio transmission outages, such as the one in North America on August 7. Extreme storms can cause radio outages lasting hours and across the globe. Such large storms can also cause more recognizable problems, such as the nine-hour power outage experienced by Hydro-Québec in 1989.
Space Weather Warning Systems
It’s not all doom and breaking rockets though. We can tell when a solar flare will leave the surface of the Sun and roughly predict when it will impact Earth, giving warnings of certain types of storms and a chance to see the aurora borealis.
Nowcasting using real-time data to understand conditions as they happen is one of our best tools. Using instruments such as ground-based radars and magnetometers on satellites, we can estimate the electromagnetic energy of space weather entering the atmosphere almost instantaneously.
As for why SpaceX lost satellites in February 2022 during a minor geomagnetic storm, it was just a matter of timing. But the loss of the satellites is a stunning reminder of the power of the universe in which we live.