A geomagnetic storm triggered by a large burst of radiation from the Sun has disabled least 40 of the 49 satellites newly launched by SpaceX as part of its Starlink internet communications network.

On February 3, SpaceX launched 49 Starlink satellites to low Earth orbit from Kennedy Space Center in Florida. Falcon 9’s second stage deployed the satellites into their intended orbit, with a perigee of approximately 210 kilometers above Earth, and each satellite achieved controlled flight.

These satellites were significantly impacted by a geomagnetic storm on February 4.

The satellites hit by the solar storm were in a temporary position. SpaceX deliberately launches them into this unusually low orbit so that any duds can quickly reenter the atmosphere and pose no threat to other spacecraft.

SpaceX, the Los Angeles area-based rocket company founded by billionaire entrepreneur Elon Musk, has launched small satellites into orbit since 2019 as part of his Starlink service for broadband internet. SpaceX has close to 2,000 Starlink satellites orbiting Earth and providing internet service to remote corners of the world. The company envisions a constellation of roughly 30,000 satellites, up from 12,000 previously planned.

What is a geomagnetic storm?

A geomagnetic storm is a major disturbance of Earth’s magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth. 

These storms result from variations in the solar wind that produce major changes in the currents, plasmas, and fields in Earth’s magnetosphere. The solar wind conditions that are effective for creating geomagnetic storms are sustained periods of high-speed solar wind, and most importantly, a southward directed solar wind magnetic field (opposite the direction of Earth’s field) at the dayside of the magnetosphere. This condition is effective for transferring energy from the solar wind into Earth’s magnetosphere.

The largest storms that result from these conditions are associated with solar coronal mass ejections (CMEs), where a billion tonnes or so of plasma from the Sun, with its embedded magnetic field, arrives at Earth. CMEs typically take several days to arrive at Earth, but have been observed, for some of the most intense storms, to arrive in as short as 18 hours. 

Solar flares, coronal mass ejections, high-speed solar wind, and solar energetic particles are all forms of solar activity. All solar activity is driven by the solar magnetic field.

Does solar activity affect Earth?

Modern society depends on a variety of technologies susceptible to the extremes of space weather. Changes in the ionosphere during geomagnetic storms interfere with high-frequency radio communications and Global Positioning System (GPS) navigation. During polar cap absorption events caused by solar protons, radio communications can be compromised for commercial airliners on transpolar crossing routes. Exposure of spacecraft to energetic particles during solar energetic particle events and radiation belt enhancements cause temporary operational anomalies, damage critical electronics, degrade solar arrays, and blind optical systems such as imagers and star trackers.

Human and robotic explorers across the solar system are also affected by solar activity. Research has shown, in a worst-case scenario, astronauts exposed to solar particle radiation can reach their permissible exposure limits within hours of the onset of an event. Surface-to-orbit and surface-to-surface communications are sensitive to space weather storms.

What is the Carrington Event?

The Carrington Event in 1859 is the largest known example of geomagnetic storm. The great geomagnetic storm of August 28 through September 3, 1859 was a famous space weather event. Auroral displays, often called the northern or southern lights, spanned several continents and were observed around the world during those days. Richard Carrington, a British astronomer, recorded the solar outburst, a white-light flare. Across the world, telegraph networks experienced disruptions and outages as a result of the currents generated by the geomagnetic storm.

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