Its a big day for The Indian Space Research Organisation (Isro) as it achieved another milestone as the Aditya Solar wind Particle Experiment (ASPEX) payload onboard India's Aditya-L1 satellite commenced its operations and started performing normally.

According to Isro, the ASPEX comprises two instruments-- the Solar wind Ion Spectrometer (Swis) and the SupraThermal and Energetic Particle Spectrometer (Steps).

While the Steps instrument was made operational on September 10, 2023, the Swis instrument was activated on November 2, 2023, and has exhibited optimal performance.

Swis, utilising two sensor units with a 360-degree field of view each, operates in planes perpendicular to one another. The instrument has successfully measured solar wind ions, primarily protons and alpha particles.

A sample energy histogram acquired from one of the sensors over two days in November 2023 illustrates variations in proton (H+) and alpha particle (doubly ionised helium, He2+) counts.

These variations were recorded with nominal integration time, providing a comprehensive snapshot of solar wind behaviour.

The directional capabilities of the Swis enable precise measurements of solar wind protons and alphas, contributing significantly to addressing longstanding questions about solar wind properties, underlying processes, and their impact on the Earth.

According to Isro, the change in the proton and alpha particle number ratio, as observed by Swis, holds the potential to provide indirect information about the arrival of Coronal Mass Ejections (CMEs) at the Sun-Earth Lagrange Point L1.

An enhanced alpha-to-proton ratio is often regarded as one of the sensitive markers of the passage of interplanetary coronal mass ejections (ICMEs) at the L1 and hence is considered crucial for space weather studies.

Notably, Aditya-L1, India's first dedicated solar mission, was launched into space on September 2 from the Satish Dhawan Space Centre (SDSC) in Andhra Pradesh's Sriharikota island.

The spacecraft, after travelling about 1.5 million km from Earth over 125 days, is expected to be placed in a Halo orbit around the Lagrangian point L1, considered closest to the Sun.

Last week, Isro chief S Somnath said that the Aditya L1 spacecraft is nearing its final phase, and manoeuvres to enter the L1 point are expected to be completed by January 7, 2024