The Earth’s atmosphere is a dynamic thing, flowing and changing, even stretching all the way past the Moon. Earlier this month, heated by a burst of solar energy, it expanded—and gobbled up dozens of recently launched SpaceX satellites, costing the company tens of millions of dollars.
On Feb. 3, SpaceX deployed 49 Starlink internet satellites from a Falcon 9 rocket. But like a tidal surge dragging boats back into a harbor, the satellites were unable to escape the drag caused by a solar storm—an increase in the electromagnetic energy the sun constantly hurls into the solar system.
Thirty-eight of the spacecraft have been pulled down into the atmosphere, according to Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Institute who tracks space activity, where they will burn up.
SpaceX’s experience reminds us that our understanding of our nearest star is not as complete as we’d like it to be. Space weather is normal—government agencies, scientists, and even private companies track it—but so far we have a very limited ability to predict it. This is becoming a more acute problem as we put more equipment in space, but understanding solar weather is also important on Earth, since these storms have the potential of disrupting key infrastructure here, too.
This recent storm was only a 1 out of 5 on NOAA’s measurement scale. But, in 1989, a major solar storm disrupted electricity in Canada, and one during the Vietnam war is thought to have set off mines at sea. An unlikely repeat of the Carrington event, a massive solar storm in 1859 that shut down telegraph networks, would be even worse in today’s far more electronic world.
An unlucky day to launch satellites
SpaceX’s satellites were particularly vulnerable because of their location at just 210 km above the planet. That’s low for satellites, which SpaceX says is for safety reasons: If any of the satellites malfunctions after launch, they will soon be dragged back to burn up in the atmosphere instead of interfering with other spacecraft.
Robert Sproles, an executive at Spire, a company operating a network of remote-sensing satellites, says SpaceX got unlucky. Typically, the kind of drag generated by the February solar storm might reduce the lifetime of a satellite by a few days or months. Because SpaceX is “very responsible” in deploying its satellites at very low altitudes before raising them to more crowded orbits, they suffered a harsh result, he said.
Before the launch, NOAA, the US weather agency, warned of a minor geomagnetic storm. Such “space weather,” caused by changing conditions on the star, heats the gasses in our planet’s atmosphere, causing it to expand. Suddenly, there was more gas where SpaceX’s satellites flew.
SpaceX didn’t respond to questions about the incident or how it incorporates space weather into its launch procedures, but did report increases of drag on their satellites that exceeded a typical launch by 50%. Ground controllers tried to position their satellites with the smallest cross-section to reduce friction from the atmosphere, but it wasn’t enough.
It’s not clear why the company didn’t try to use the spacecraft’s propulsion systems to raise them to a higher altitude—perhaps engineers were concerned about magnetic energy frying components, or perhaps the drag was too strong for the satellites’ ultra-efficient but low-thrust electronic propulsion system.
While SpaceX hasn’t confirmed its losses, industry sources believe the spacecraft in question cost about $500,000 each to produce, and because they are upgraded versions with optical laser communications, likely more. The launch itself cost SpaceX on the order of $40 million, based on Elon Musk’s past estimates of the cost of a re-flown Falcon 9 rocket booster. All told, the company might have lost $80 million or more.
Space weather is a real concern for spacecraft operators, who must design their vehicles to survive radioactive and magnetic conditions that the atmosphere protects us from on the ground. As recently as 2014, a mission to the International Space Station was canceled after engineers at the company Orbital Sciences became concerned that space weather might fry sensitive electronics onboard.
What can we do about solar weather?
One issue is that we still don’t have much ability to predict the solar weather. Sproles says forecasts of changing solar weather come within a few hours, not a few days. “If you had more advanced warning, you could shut down subsystems, it would be about safeing your satellite with more notice,” he says.
Scientists who study the sun say the proliferation of new observatories, like the Solar Dynamics Observatory, and probes, like the Parker Solar Probe, make this an exciting time to study solar flares and other phenomena on the surface of the sun that create solar weather.
Last week, NASA announced two new projects to study the sun with space-based sensors. One of them, called MUSE, will launch a novel spectrograph—a sensor that allows scientists to carefully analyze the properties of light generated by the sun—with the ability to take longer exposures over a wider field of view.
“We’re going to capture the properties of the gasses in the solar atmosphere 40 to 100 times faster than any previous or currently planned spectrograph,” Dr. Bart de Pontieu, a scientist at Lockheed Martin’s Solar and Astrophysics laboratory and the mission’s principal investigator, says.
Rather than seeing the super-heated gas that makes up the sun at a resolution of thousands of kilometers, the new instrument will depict its movement and structure at sizes of hundreds of kilometers. That data, de Pontieu says, will help scientists test theories about solar physics and help generate more accurate models of the sun’s behavior.
That, in turn, will help scientists working to predict changing solar weather. “MUSE is focused on understanding the physical processes behind space weather events,” De Pontieu says. “Getting a better physical understanding will inevitably lead to better predictions.”