India's first solar mission will study about the Sun

 Aditya-L1, India's pioneering space-based solar observatory focused on studying the Sun, has begun its scientific mission. On September 19, 2023, it successfully exited Earth's gravitational influence, following the completion of its fifth and final Earth-bound maneuver known as the Trans-Lagrangian Point 1 Insertion (TL1I) maneuver. Aditya-L1 is now on its way to its destination, a halo orbit around Lagrange Point 1 (L1), a journey that will take about 110 days.

This strategic location at L1, 1.5 million kilometers from Earth, offers many advantages. This allows Aditya-L1 to conserve energy by reducing fuel consumption while giving the spacecraft an uninterrupted view of the Sun throughout its five-year mission duration.

Aditya-L1 is equipped with seven scientific instruments, including four remote sensing devices and three in-situ instruments. Remote sensing payloads include the Visible Emission Line Coronagraph (VELC), the Solar Low Energy X-ray Spectrometer (SoLEXS), the Solar Ultraviolet Imaging Telescope (SUIT), and the High Energy L1 Orbiting X-ray Spectrometer (HEL1OS). On the other hand, the in-situ payloads include the Aditya Solar Wind Particle Experiment (ASPEX), the Plasma Analyzer Package for Aditya (PAPA) and the Advanced Tri-Axial High Resolution Digital Magnetometer.

The VELC, acting as the primary payload, is designed as a reflective coronagraph, effectively blocking sunlight to reveal only the solar corona. Equipped with a multi-slit spectrograph, it spreads electromagnetic radiation from the Sun into a spectrum and conducts imaging and spectroscopy of the solar corona.

SoLEXS, a soft X-ray spectrometer, focuses on studying solar flares by measuring the solar soft X-ray flux, which indicates the amount of low-energy X-ray emission originating from the Sun's surface.

HEL1OS, a hard X-ray spectrometer, searches for solar flares by measuring high-energy X-rays with shorter wavelengths emitted by the Sun.

SUIT, an ultraviolet telescope, captures images of the solar disk in the near-ultraviolet wavelength range, enabling observations of the photosphere and chromosphere, which represent the innermost and middle layers of the solar atmosphere, respectively.

ASPEX acts as a particle analyzer, examining various particles in the solar wind, including protons and heavy ions in different directions. It consists of two subsystems: the Solar Wind Ion Spectrometer (SWIS) and the Superthermal and Energetic Particle Spectrometer (STEPS).

SWIS, a low-energy spectrometer, focuses on measuring protons and alpha particles in the solar wind.

STEPS, Aditya-L1's inaugural payload for conducting scientific experiments, acts as a high-energy spectrometer, evaluating high-energy ions in the solar wind.

PAPA plays an important role in understanding the composition of the solar wind, analyzing solar wind ions, and examining electrons and heavy ions in the solar wind in different directions.

The magnetometer, equipped with two sets of magnetic sensors — one at the tip of a six-meter deployable boom and the other three meters away from the spacecraft — monitors the low-intensity interplanetary magnetic field in space. These magnetometers probe magnetic fields at Lagrange points to explain how solar activity affects the magnetic fields in the interplanetary medium.

Aditya-L1 is poised to provide invaluable insights into a number of important areas, including the problem of coronal heating, dynamics of space weather, solar flares and the propagation of particles and fields through the interplanetary system. Its finely tuned payloads are specially designed to observe the solar atmosphere, particularly the chromosphere and corona, and to carry out experiments to enhance our understanding of the local environment at L1.

Aditya-L1's main scientific objectives include investigating the dynamics of the upper solar atmosphere, such as the chromosphere and corona; Investigation of the in-situ particle and plasma environment surrounding L1 to understand the impact of solar particle dynamics in this region; Measurement of temperature, velocity and plasma density within the corona; and identification of sequential processes occurring within different layers of the solar atmosphere, shedding light on the origin of solar flares.