ISRO captures signatures of recent solar storm

The Indian Space Research Organisation (ISRO) has captured the signatures of the recent solar eruptive events from the earth, the Sun-earth L1 point, and the moon.

A powerful solar storm impacted the earth last week, triggered by the highly active region AR13664. This region unleashed a series of X-class flares and coronal mass ejections (CMEs) directed at the earth.

“This is the biggest geomagnetic storm since 2003 in terms of its strength, as the flaring region on the Sun was as big as the historically important Carrington event that took place in 1859. Multiple X-class flares and CMEs have hit the earth in the past few days. This had severe effects over high latitudes where trans-polar flights are already being reported to get diverted. More events are expected in the next few days,” ISRO said.

However the space agency said that the Indian sector was less affected as the main hit of the storm happened in the early morning of May 11, when the ionosphere was not developed fully.

“Also, being at lower latitudes, widespread outages haven’t been reported in India,” ISRO said.

Observations from ground

ISRO said that the global navigation satellite system network observations at the National Atmospheric Research Laboratory at Gadanki, Andhra Pradesh, showed a decrease of the total electron content (TEC) by more than 50% from May 10 midnight to May 11 morning.

“On May 11 daytime, TEC was high by about 10% with large variations indicating disturbed ionosphere. In the evening TEC is nearly 30% more. No L band scintillation has been observed. Radar observations showed no bubble, consistent with TEC and scintillation observed by GNSS receivers,” ISRO said.

It added that the observations by the Thumba node of the Indian Network for Space Weather Impact Monitoring network was more dramatic.

“This is expected, as the ionospheric ring current, which is enhanced during geomagnetic storms, passes over the sky of Thumba,” ISRO said.

Observations from space

ISRO also said it had mobilised all its observation platforms and systems to record the signatures of this event and that both Aditya-L1 and Chandrayaan-2 have made observations and signatures have been analysed.

It said that the ASPEX payload on-board Aditya-L1 has been showing high speed solar wind, high temperature solar wind plasma, and energetic ion flux so far.

“The X-ray payloads on-board Aditya-L1 (SoLEXS and HEL1OS) have observed the multiple X- and M-class flares from these regions during the last few days while the in-situ magnetometer (MAG) payload has also observed the events as it passed by the L1 point,” ISRO said

While Aditya-L1 observes the Sun from the first Sun-earth Lagrange point (l1), the Chandrayaan-2 orbiter also captured signatures of these “solar eruptive events” from its orbit around the moon’s poles.

Indian spacecraft health

According to ISRO, its Master Control Facility team was on alert and watchful of any geomagnetic activity experienced by earth-orbiting spacecrafts.

“Momentum wheel speed deviations were observed along with MTC current saturation in few spacecraft. Spacecraft with one-sided panels had predominant signature variations which required frequent momentum dumping. Otherwise, overall operations were normal. No single event upsets were seen. Star Sensor (SS-2) in INSAT-3DS and Star Sensor (SS-3) in INSAT-3DR were turned off as per mission. Other than this there has not been any major upsets or anomaly observed in any of the 30 GEO spacecrafts so far,” ISRO said.

It added that none of the earth-observation satellites of ISRO, which were visible from ISRO’s ground stations, suffered any upsets. The ISRO Navigation Centre has also reportedly not noticed any significant degradation in the ‘Navigation with Indian Constellation‘ (NavIC) service metrics so far, indicating no or negligible impact due to the solar storm.