Bangalore - The Indian Space Research Organisation (ISRO), on Saturday marked a significant achievement with the initiation of operations for the Aditya Solar Wind Particle Experiment (ASPEX) payload aboard the Aditya-L1 satellite.

ISRO reported that ASPEX consists of two instruments, namely the Solar Wind Ion Spectrometer (Swis) and the SupraThermal and Energetic Particle Spectrometer (Steps).

The Steps instrument became operational on September 10, 2023, while the Swis instrument was activated on November 2, 2023, demonstrating optimal performance. Swis, equipped with two sensor units offering a 360-degree field of view each, operates in mutually perpendicular planes. The instrument has effectively measured solar wind ions, predominantly protons and alpha particles.

An energy histogram obtained from one of the sensors over two days in November 2023 illustrates variations in proton (H+) and alpha particle (doubly ionized helium, He2+) counts. These variations were recorded with nominal integration time, presenting a comprehensive snapshot of solar wind behavior.

Swis's directional capabilities enable precise measurements of solar wind protons and alphas, significantly contributing to addressing longstanding inquiries about solar wind properties, underlying processes, and their impact on Earth. ISRO notes that the observed change in the proton and alpha particle number ratio by Swis holds the potential to offer indirect information about the arrival of Coronal Mass Ejections (CMEs) at the Sun-Earth Lagrange Point L1.

An elevated alpha-to-proton ratio is often considered a sensitive marker of the passage of interplanetary coronal mass ejections (ICMEs) at the L1 point, making it crucial for space weather studies. Aditya-L1, India's inaugural dedicated solar mission, was launched on September 2 from the Satish Dhawan Space Centre (SDSC) on Sriharikota Island in Andhra Pradesh.

Having traveled approximately 1.5 million km from Earth over 125 days, the spacecraft is anticipated to be positioned in a Halo orbit around Lagrangian point L1, which is considered the closest point to the Sun. ISRO Chief S Somnath mentioned last week that the Aditya L1 spacecraft is entering its final phase, with maneuvers to reach the L1 point expected to be completed by January 7, 2024.