Aditya-L1’s HEL1OS Captures the First High-Energy X-ray Glimpse of Solar Flares

The Indian Space Research Organisation (ISRO) continues to make groundbreaking strides in the field of space research and exploration. In a recent development, ISRO’s Aditya-L1 spacecraft has captured the “First Light Of Sun” through its High Energy L1 Orbiting X-ray Spectrometer (HEL1OS). Thus marking a significant achievement in the study of solar flares and the Sun’s behavior.

Aditya-L1: A Remarkable Solar Mission

Aditya-L1 is a pioneering spacecraft designed by ISRO for the primary purpose of observing the solar corona remotely. Positioned at the Sun-Earth Lagrangian point (L1), which is about 1.5 million kilometers away from Earth, this mission is a testament to India’s commitment to exploring the Sun’s mysteries.

The Aditya-L1 mission is a significant milestone as it is India’s first dedicated space mission for the observation of the Sun. Equipped with seven payloads, it aims to study various aspects of the Sun, including the photosphere, chromosphere, and the outermost layers of the Sun, known as the corona, in different wavebands.

HEL1OS: A Spectrometer for Solar Flare Research

HEL1OS, the High Energy L1 Orbiting X-ray Spectrometer, is a crucial instrument on board the Aditya-L1 spacecraft. Recently, it achieved a remarkable feat by capturing the first high-energy X-ray glimpse of solar flares. This achievement is a testament to the capabilities and objectives of HEL1OS.

Solar flares are sudden and intense brightenings of the Sun’s atmosphere, leading to enhanced emissions in various wavelengths across the electromagnetic spectrum. These emissions encompass radio waves, optical light, ultraviolet, soft X-rays, hard X-rays, and even gamma-rays. 

While solar flares have been studied for decades, characterizing and understanding the initial impulsive phase, particularly in hard X-rays, has been challenging due to its rapid changes and spectral complexity.

HEL1OS was developed by the Space Astronomy Group of the U R Rao Satellite Centre, ISRO, Bengaluru. Its mission is to overcome these challenges by using a set of detectors tuned to different energy ranges, providing high spectral and time resolution measurements. It’s a significant step in advancing our understanding of solar flares.

Video Credit : The Economic Times

Unlocking Solar Flare Mysteries

The data collected by HEL1OS will offer researchers the opportunity to delve deeper into the mysteries of solar flares. With its fast timing and high-resolution spectra, HEL1OS will allow scientists to study the explosive energy release and electron acceleration during the impulsive phases of solar flares.

As of now, HEL1OS is in the process of fine-tuning thresholds and calibration operations, following its commissioning on October 27, 2023. The instrument is all set to monitor high-energy X-ray activity from the Sun, shedding light on the dynamic behavior of our nearest star.


ISRO’s Aditya-L1 mission and HEL1OS spectrometer represent a significant leap forward in solar research. The successful capture of the first high-energy X-ray glimpse of solar flares opens the door to a better understanding of the Sun’s behavior and the complex processes that occur during solar flares. This achievement reaffirms India’s position as a leader in space exploration and underscores the importance of continued research into our nearest celestial neighbor, the Sun.