Explained: Geomagnetic Storm That Killed Starlink Satellites

Elon Musk’s Starlink lost dozens of satellites that were caught in a geomagnetic storm a day after their launch on February 3. Up to 40 of the 49 satellites were hit, Starlink said, knocking them out of orbit before they could be put into service.

“The second stage of (Rocket) Falcon 9 deployed the satellites to their intended orbit, with a perigee of approximately 210 km above Earth, and each satellite achieved controlled flight. Unfortunately, the satellites deployed on Thursday (February 3) were significantly impacted by a geomagnetic storm on February 4,” Starlink said in a statement Tuesday.

The satellites were designed to burn up upon re-entry into Earth’s atmosphere and did not create debris in space. However, the loss of 40 satellites – most of a launch batch – in a single solar event has been described as “unheard of” and “enormous”.

Solar storms/flares

Solar storms are magnetic plasmas ejected at high speed from the solar surface. They occur during the release of magnetic energy associated with sunspots (‘dark’ regions of the Sun that are cooler than the surrounding photosphere) and can last for minutes or hours. The solar storm that de-orbited the satellites occurred on February 1 and 2, and its powerful trails were observed on February 3.

“Emerging data suggests that the passage of the latter part of the storm, with its high-density core, possessed speeds greater than those recorded during the storm’s arrival – something we did not expect,” said physicist Prof Dibyendu Nandi, Head of Center of Excellence in Space Science India (CESSI) at Indian Institute of Science Education and Research (IISER), Kolkata.

The storm was unusual, unexpectedly massive and of a kind not seen in the recent past, Prof Nandi said.

Effect on Earth

Not all solar flares reach Earth, but approaching solar flares/storms, solar energetic particles (SEPs), high-velocity solar winds, and coronal mass ejections (CMEs) can impact the space weather in near-Earth space and in the upper atmosphere.

Solar storms can affect operations of space-dependent services like global positioning systems (GPS), radio, and satellite communications. Geomagnetic storms interfere with high frequency radio communications and GPS navigation systems. Aircraft flights, power grids and space exploration programs are vulnerable.

CMEs, with charged ejectiles of matter moving at millions of miles per hour, can potentially create disturbances in the magnetosphere, the protective shield that surrounds the Earth. Spacewalking astronauts face health risks related to possible exposure to solar radiation outside of Earth’s protective atmosphere.

Predict solar storms

Solar physicists and other scientists use computer models to predict solar storms and solar activities in general. The February 1-2 phenomenon that destroyed Starlink’s satellites was predicted on January 29.

“Current models are able to predict the arrival time of a storm and its speed. But the structure or direction of the storm still cannot be predicted,” Prof Nandi said.

Certain orientations of the magnetic field can produce a more intense response from the magnetosphere and trigger more intense magnetic storms.

With the world’s growing reliance on satellites for almost all activities, there is a need for better space weather forecasts and more effective means of protecting satellites.

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