Solar storm: Aditya-L1 and Chandrayaan-2 have recorded and analysed signatures of the recent powerful solar eruptive events from the Earth, the Sun-earth L1 point, and the moon, the Indian Space Research Organisation (ISRO) said on Tuesday. 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.
According to ISRO, the resulting geomagnetic storm was the most intense since 2003, leading to disruptions in communication and GPS systems. "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," ISRO said in a statement.
Multiple X-class flares and CMEs have hit the Earth in the past few days, the space agency said. "This (CME) 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 noted.
The space agency said that the Indian sector got less affected as the main event of the storm happened in the early morning of May 11, when the ionosphere had not developed fully. "Also, being at lower latitudes, widespread outages haven't been reported in India. Ionosphere was very turbulent over the Pacific and American sectors," it said.
ISRO said it has mobilised all its observation platforms and systems to record the signatures of this event. Both Aditya-L1 and Chandrayaan-2 have made observations and signatures have been analysed.
Observations by Aditya-L1
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 till now. "The Solar wind Ion Spectrometer (SWIS) has captured the enhancement of the alpha particle and proton flux of the solar wind as a signature of this solar eruptive event," the ISRO said.
Aditya L1's SupraThermal and Energetic Particle Spectrometer (STEPS) also measured the flux of the solar wind ions at seven energy ranges. "A steady rise in the energetic ion fluxes during the event has been noticed," the agency added.
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," the agency said.
Observations by Chandrayaan-2
While the Aditya-L1 observes the Sun from the first Sun-Earth Lagrange point, the Chandrayaan-2 orbiter has also captured the signatures of these solar eruptive events from the lunar polar orbit.
"XSM has observed many interesting phenomena associated with this geomagnetic storm. The large solar flares, manifested as spikes, are autonomously identified by the onboard logic of XSM, when the internal mechanism was activated to reduce the incident X-ray flux by bringing a filter in front of the detector, so as to prevent its saturation. While the XSM primarily monitors solar X-rays, it has also provided information about the local high energy particle environment by means of counting the events when the upper level discriminator (ULD) threshold is crossed.
The ULD event light curve over the past five days, clearly shows the enhancement of the local charge particle concentration from 9th May onwards. The dips observed in the XSM ULD light curve are due to the shadow effect arising from orbit of the spacecraft around the Moon," the ISRO said.
Spacecraft health
According to ISRO, its Master Control Facility (MCF) 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.
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