On March 23, sky observers marveled at a gorgeous display of northern and southern lights. It was a reminder that when our Sun gets active, it can spark a phenomenon called “space weather.” Aurorae are among the most benign effects of this phenomenon. At the other end of the space weather spectrum are solar storms that can knock out satellites. The folks at Starlink found that out the hard way in February 2022. On January 29 that year, the Sun belched out a class M 1.1 flare and related coronal mass ejection. Material from the Sun traveled out on the solar wind and arrived at Earth a few days later. On February 3, Starlink launched a group of 49 satellites to an altitude only 130 miles above Earth’s surface. They didn’t last long, and now solar physicists know why.
A group of researchers from NASA Goddard Space Flight Center and the Catholic University of America took a closer look at the specifics of that storm. Their analysis identified a mass of plasma that impacted our planet’s magnetosphere. The actual event was a halo coronal mass ejection from an active region in the northeast quadrant of the Sun. The material traveled out at around 690 kilometers per second as a shock-driving magnetic cloud. Think of it as a long ropy mass of material writhing its way through space. As it traveled, it expanded and at solar-facing satellites — including STEREO-A, which took a direct hit from it — made observations. Eventually, the cloud smacked into Earth’s magnetosphere creating a geomagnetic storm.
The atmosphere thickened enough that it affected the newly launched Starlink stations. They started to experience atmospheric drag, which caused them to deorbit and burn up on the way down. It was an expensive lesson in space weather and provided people on Earth with a great view of what happens when satellites fall back to Earth. It was also that could have been avoided if they’d delayed their launch to account for the ongoing threat.
Source: NASA Reveals What Made an Entire Starlink Satellite Fleet Go Down – Slashdot
Robin Edgar
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