ISRO’s Aditya L1 and Chandrayaan-2 get front-row seats to the strongest solar storm in over 20 years

The Sun has been throwing some major temper tantrums lately, its active sunspot AR13664 directing multiple intense X-class flares and coronal mass ejections (CMEs) towards our planet since the beginning of May. A recent geomagnetic storm, deemed to be the strongest since 2003, struck Earth earlier this month, causing disruptions to communication and GPS systems.

The Indian space agency ISRO, which had front-row seats to the debacle, was able to remain on top of these events. On high alert during the entire solar drama, the space agency’s satellites were able to dodge the worst of the storm’s impacts while its spacecraft Aditya-L1 and Chandrayaan-2 managed to collect quite a bit of data on the event.

Aditya-L1 is stationed at a special point between Earth and the Sun, constantly monitoring our fiery neighbour. It used its ASPEX instrument to measure the fast solar wind, hot plasma, and energetic particles released during the solar storm. It also used its X-ray sensors to directly see the powerful X-class flares, and its magnetometer picked up changes in the magnetic field between planets.

While Aditya-L1 kept a watchful eye on the Sun, Chandrayaan-2, orbiting the Moon, provided another vantage point. The spacecraft used its X-ray monitor (XSM) to observe various aspects of the storm. It tracked X-rays from the Sun, automatically identified strong flares, and monitored the local high-energy particle environment. The data from XSM showed an increase in nearby charged particles starting around May 9, with brief dips due to the spacecraft's movement around the Moon.

As for ISRO’s 30 other GEO spacecraft or Earth Observation Satellites, no major upsets or anomalies were reported. However, the solar storm did spark an increase in atmospheric density, which led to increased orbit decay — where the orbital radius decreases due to atmospheric drag. According to ISRO, some satellites experienced decay 5-6 times higher than usual on May 11.

The intense solar activity caused slight deviations in their momentum wheels, requiring adjustments. But these were just bumps on the road, and no major damage or loss of function was reported.

By capturing the details of this solar storm, ISRO has gained valuable insights into the Sun's behaviour. This data will be crucial for developing better prediction models and safeguarding our infrastructure from future solar events. So, the next time the Sun throws a tantrum, we'll be even more prepared, thanks to ISRO's watchful eyes in space.