The recent loss of dozens of Elon Musk’s Starlink satellites due to a powerful geomagnetic storm has drawn attention to the unpredictable nature of space weather and its potential impact on our increasingly satellite-dependent world. Just a day following their launch, over 40 Starlink satellites were swept into a solar storm that proved disastrous. Although these satellites were intended to disintegrate upon re-entry into Earth’s atmosphere without leaving any debris, the sheer number of satellites lost to a single solar event is both unusual and alarming.
About Starlink
Starlink, a project of SpaceX, aims to establish a broadband network using a constellation of potentially thousands of orbiting satellites. Outfitted with Hall thrusters that utilize electricity and krypton gas, these satellites are maneuverable in orbit, able to maintain altitude, and can guide themselves back into the atmosphere at the end of their life cycle.
Understanding Geomagnetic Storms
Geographical storms are marked disturbances in Earth’s magnetosphere brought on by efficient energy transfers from the solar wind into the surrounding space environment. The occurrence of such events align with the release of magnetic energy connected to sunspots, dark regions on the Sun’s surface that are cooler than the surrounding photosphere or the lowest layer of the solar atmosphere. These disruptions, caused by variations in solar winds, lead to significant alterations in the currents, plasmas, and fields within Earth’s magnetosphere.
The most effective conditions for producing geomagnetic storms include sustained periods of high-speed solar wind and a southward-directed solar wind magnetic field. This orientation allows for maximum energy transfer from the solar wind into Earth’s magnetosphere.
The largest storms correspond with solar Coronal Mass Ejections (CMEs), where a billion tons of plasma carrying its embedded magnetic field reaches Earth.
The Impact of Solar Storms on Earth
Though not all solar flares reach the Earth’s surface, those that do, including Solar Energetic Particles (SEPs), high-speed solar winds, and Coronal Mass Ejections (CMEs), can significantly affect space weather in near-Earth space and the upper atmosphere.
These storms can disrupt space-dependent services such as GPS, radio, and satellite communications. Vulnerable to these disturbances are aircraft flights, power grids, and space exploration programmes.
Coronal Mass Ejections (CMEs), charged with matter travelling at extreme speeds, have the potential to disrupt the magnetosphere, our planet’s protective shield. Astronauts conducting extravehicular activities risk exposure to harmful solar radiation outside the Earth’s protective atmosphere due to these disruptions.
Predicting Solar Storms
Scientists employ computer models to forecast solar storms and other solar activities. While present models can predict a storm’s arrival time and speed, they are not yet capable of determining its structure or orientation. However, certain orientations of the magnetic field can induce stronger responses from the magnetosphere and ignite more intense magnetic storms.
Given the world’s rising dependence on satellite technology, there is an urgent need for more accurate space weather forecasts and more effective protective measures for satellites.
