The company’s new policy is very strict.
The company’s new policy is extremely rigorous. fties in space is tricky business and it’s even trickier when you don’t know what kind of space weather you’ll be dealing with
When there isn’t a cloud in the sky, I’ll sometimes check the weather forecast to avoid getting soaked if I leave home without an umbrella. However, when it comes to launching satellites, keeping them safe from space weather is a bit more complicated. In 2022, SpaceX Engineers learned this the hard way. They had prepped to shoot another round of Starlink satellites into orbit, having checked the space weather forecast and run their own models to ensure everything would be A-OK. Unfortunately, out of the 49 satellites that launched, 38 fell out of the sky - a much worse outcome than having to walk around in wet clothes.
In order to avoid a similar incident in the future, scientists and Engineers must learn more about how space weather works in the area surrounding Earth. Space weather is driven mostly by the Sun’s activity, such as how often and intensely it burps matter and light into space. The way Starlink satellites operate makes them particularly vulnerable to bad space weather.
Like many modern satellites, the Starlink constellation resides in low Earth orbit, ranging from 160 to 1,200 or 2,000 kilometers above Earth’s surface, depending on who you ask. SpaceX targets the lowest part of low Earth orbit, launching each Starlink satellite into an initial orbit of 210 kilometers. This is done so that if a satellite malfunctions, it will quickly fall and burn up in the atmosphere, thus preventing dead satellites from floating around like zombies - an incredibly important safety measure.
Once a Starlink satellite is functioning correctly, it can use its little booster rockets to push itself into a more permanent orbit at 500 kilometers. However, it’s the same phenomenon that helps prevent Starlink zombies that caused those 38 to tumble out of the sky - the drag that comes from flying through the few but still present molecules of Earth’s atmosphere. In fact, the drag was 50 percent higher than normal, at least compared to previous launches, and much higher than SpaceX Engineers were expecting from the forecast.
It turns out the extra drag was caused by a storm in space that they’d underestimated before the Starlink launch. The Sun had ejected a large amount of plasma in an event called a coronal mass ejection, which traveled through space and reached Earth on launch day. The plasma’s magnetic field interacted with the Earth’s magnetic field, transferring some extra energy into the atmosphere and inflating it, sending more molecules to higher altitudes and making the air around any given satellite more dense and more difficult to move through.
By the time Engineers figured out how bad the storm’s effects were, it was too late for most of the satellites. So why was the weather forecast - or the models that the Starlink team ran based on that forecast - so wrong? A group of scientists at the Space Weather Prediction Center monitor the weather in space and issue warnings if that weather will impact a launch. They are based at the National Oceanic and Atmospheric Administration (NOAA), the same group that gives us Earth-based weather reports. While they knew this space storm was coming, they didn’t think it would cause damage. In fact, they classified it as minor, but they didn’t report any effects the storm would have on atmospheric drag. So the Starlink team had to run the numbers themselves and they miscalculated.
That was the drama happening in very low Earth orbit, but what about everywhere else? Putting satellites in space is tricky business, and it’s even trickier when you don’t know what kind of space weather you’ll be dealing with. .
Beyond low earth orbit, other common spots to place a satellite include geosynchronous orbit at 35,000 kilometers, and medium earth orbit - a zone between low earth orbit and geosynchronous orbit. At these higher altitudes, sudden increases in drag aren’t much of a threat, as there isn’t a large enough change in the number of air molecules to make much of a difference. However, space weather can still cause two main types of damage. First, it can increase the abundance of high energy electrons, which can then cause an electric charge to build up on a satellite surface or inside its circuitry; worst case scenario, this charge creates an electrical short that damages the circuits or the solar panels responsible for powering the satellite. Second, a satellite can be struck by a single charged particle that damages its circuitry.
It isn’t clear how often high altitude satellites experience space weather related damage, as it isn’t in companies’ best interest to report their satellites’ failures, and they might not even know if a failure was caused by space weather. Therefore, science doesn’t have much data to go on. However, one thing we do know is that all satellite operators are in for a rocky few years. We are currently in a new-ish solar cycle called Solar Cycle 25, which started in 2019 and is building towards maximum activity in 2025. It has already been a more active solar cycle than predicted, so even more plasma eruptions are probably on the way.
It is important to better understand how space weather impacts satellites in all orbits, but it is especially important for satellites in low and very low earth orbits. These satellites can be cheaper to launch, and can offer more detailed images and higher connection speeds, so companies and governments are planning to launch many more constellations in the coming years.
Shortly after the incident, SpaceX modified their launch program, sending the next batch of Starlinks to a slightly higher initial altitude of 300 kilometers, giving the satellites more time and less drag to boost themselves into their final orbit. This approach has worked, and researchers are also working on improving their space weather forecasts. Starlink is sharing information with NOAA so they have more data to refine their prediction models, and NASA is planning to launch a constellation of satellites dedicated to studying how different types of space weather change the environment where low earth orbit satellites operate.
Hopefully, all these efforts will help everything engineers launch into space get where they’re supposed to go and stay where they’re supposed to stay, as the last thing anyone wants to hear in their weather forecast is a chance of satellite rain.