Aditya L1

The Indian Space Research Organisation (ISRO) recently announced that it had reached a groundbreaking milestone in solar research when its High-Energy L1 Orbiting X-ray Spectrometer (HEL1OS) aboard India’s first solar space observatory, Aditya L1, “recorded the impulsive phase of a high-energy solar flare” during its maiden observation on October 29, 2023. HELIOS was developed by the Space Astronomy Group at ISRO’s UR Rao Satellite Centre (URSC) in Bengaluru.

HEL1OS has been meticulously designed to monitor high-energy X-ray activity emitted by the Sun with fast timing measurements and high-resolution spectrums, besides quasi-periodic pulsations of hard X-rays, enabling scientists to study these high-energy emissions and electron acceleration and transport during impulsive phases of solar flares.

Though Aditya L1 mission’s major scientific goal is to carry out a larger, comprehensive study of the Sun’s dynamics and its over-arching influence on Earth’s climate, in particular, and space weather in general, by studying solar phenomena up close, in real-time, its immediate mission is to study how solar storms and flares impact Earth and human space explorations, leading to more precise forecasts of space weather that result in reducing potential harmful effects of these storms on space missions and technologies on Earth.

“Sun activities can also cause space weather events that pose risks to astronauts and affect Earth’s ionosphere layer in Earth’s upper atmosphere that contains ions and free electrons. This layer plays a critical role in influencing global communication and navigation systems, besides reflecting radio signals. The Aditya L1 mission’s major goals are to study the science behind solar corona and its heating mechanism, the origin of coronal mass ejections (CMEs) and flares and temperature anisotropy, apart from near-earth space weather,” explained space expert Girish Linganna.

What are these Solar eruptions and flares? Linganna explains that solar flares are huge explosions that originate from sudden, intense energy being released from the Sun’s magnetic fields and outer atmosphere in the form of high-intensity bursts of radiation in all wavelengths across the electromagnetic spectrum—mostly in the form of radio, optical, X-rays, ultra-violet light rays and gamma rays, which can reach Earth in a matter of a few hours or days, creating magnetic storms in Earth’s atmosphere lasting days. “Long-lasting flares are, sometimes, accompanied by coronal mass ejections (CMEs)—events where magnetic fields lash out a huge amount of stellar material in the form of plasma ejected by the Sun. These storms erupting on the Sun’s surface and flares emitted by it can extensively damage space satellites, besides Earth’s communication networks and power grids,” remarked Linganna.

Space experts point out that solar flares are classified into several categories: B, C, M and X. The ‘B class’ ones are minor solar flares, and ‘X class’ the most potent. ‘C class’ flares are not so significant and have very little impact on Earth. Medium-size, or ‘M class’, flares typically cause radio blackouts for a brief period of time, mainly affecting Earth’s polar regions. Sometimes, small radiation storms are after-effects of ‘M class’ flares. But ‘X class’ flares are intense events that may result in radio blackouts worldwide and radiation storms in the upper atmosphere. An ‘X class’ flare is 10 times stronger than an ‘M class’ one and 1,000 times more powerful than its ‘B class’ counterpart.

Solar flares can cause radiation storms in the upper atmosphere, radio blackouts across the world, transformer explosions, widespread mobile phone outages and magnetic field fluctuations reaching Earth. These eruptions and flares can be dangerous for space missions, astronauts and satellites up there. X-rays are a type of very energetic light that we cannot see with our naked eyes, but they can penetrate such things as the skin and muscles.

Experts further point out that solar activity is a potential threat to the internet as when a solar flare happens, the bright radiation is followed by the coronal mass ejection (CME), which can shoot off into a random direction in space. However, it is usually possible to predict if they are headed towards Earth. This gives about 18 hours of warning, maybe 24, before those particles start playing havoc with Earth’s magnetic field.

In such an event, inductive currents driven to the surface of the Earth can almost work backwards and things one thought were relatively safe could get impacted. “The power grid, underground fibre optic cables with copper sheaths, communications equipment, satellites, navigation and GPS systems and radio transmitters all become vulnerable. The very core of the Internet comprises extremely delicate electronics and a solar superstorm could really sizzle the system for prolonged periods—maybe, several weeks or even months taking into account the time it would take to put all of the infrastructure up on its leg and running again. But, we are not simply talking of communications—we also have to consider what the downtime would cost in terms of the world’s business and finances,” pointed out Linganna.

Flares reach Earth in roughly 8 minutes and the clock starts ticking for the magnetic field to go down in just 18-24 hours. So, every minute counts and a prior warning would enable scientists to put satellites in safe mode and take transformers offline from the grid to avoid sizzling them.