Context: India's first solar mission launch comes 10 days after the historic landing of the Chandrayaan-3. Aditya-L1, which will be placed in a halo orbit after a four-month journey, will study how the Sun's radiations, heat and magnetic field affects us.

• Carried into space by ISRO’s workhorse Polar Satellite Launch Vehicle (PSLV), Aditya, which means sun in Sanskrit, embarks on a 127-day journey to study solar winds.

This mission aims to achieve the following

• Scientific Understanding: The mission’s primary objective is to deepen our understanding of the Sun, its radiation, magnetic fields, and the flow of particles.

• Space Weather Forecasting: By studying the Sun’s behaviour, the mission can contribute to predicting space weather events, such as solar flares, that can disrupt satellite communications and other technologies on Earth.

• Technological Advancement: Developing a space-based observatory to study the Sun demonstrates India’s technological prowess in space exploration and adds to its reputation in the global space community.

• International Collaboration: Participating in solar research aligns with international efforts to understand the Sun and its effects.

• Education and Inspiration: The mission inspires future scientists, engineers, and researchers by showcasing India’s achievements in space science and encouraging the pursuit of space-related careers.

• Data for Innovation: The collected data can lead to innovations in technology, materials science, and various other fields that can benefit India’s technological landscape.

About the Mission

• Purpose: Aditya-L1 aims to study the Sun from a halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth systems, about 1.5 million km away from Earth.

• Mission Objective: To study the Sun, its upper atmospheric dynamics (chromosphere and corona), and understand the physics of the solar corona and its heating mechanism for the five-year time period.

• Launch Vehicle: Polar Satellite Launch Vehicle (PSLV)

• Orbit: L1 orbit (First Lagrange point of the Sun-Earth system)

• Primary Payload: Visible Emission Line Coronagraph (VELC)

• Other Payloads: Solar Ultraviolet Imaging Telescope (SUIT), Solar Low Energy X-ray Spectrometer (SoLEXS), High Energy L1 Orbiting X-ray Spectrometer (HEL1OS), Aditya Solar wind Particle EXperiment (ASPEX), Plasma Analyser Package for Aditya (PAPA)

• Significance of VELC: VELC is a solar coronagraph capable of simultaneous imaging, spectroscopy, and spectro-polarimetry. It can image the solar corona down to 1.05 times the solar radius.

• Purpose of Studying the Sun:  To gain a deeper understanding of the Sun’s radiation, heat, flow of particles, and magnetic fields; provide clues about the high temperature of the solar corona; understand space weather dynamics; and offer early warnings for solar events.

• Importance of L1 Point: L1 point provides an unobstructed view of the Sun, even during phenomena like an eclipse; allows payloads to directly observe the Sun; makes the mission fuel-efficient.

• Significance of Lagrange Points: Lagrange points are equilibrium positions in space where the gravitational forces of two large bodies, like the Earth and the Sun, produce enhanced regions of attraction and repulsion.

• Benefits of Studying the Sun from Space : Provides more detailed information due to the absence of Earth’s atmosphere; helps understand solar phenomena; enables monitoring of solar events and their potential impacts on Earth.

Objectives of ISRO Aditya L1 Mission

• It will study Solar upper atmospheric (chromosphere and corona) dynamics.

• It will do the study of chromospheric and coronal heating, physics of the partially ionized plasma, initiation of the coronal mass ejections, and flares.

• It will observe the in-situ particle and plasma environment providing data for the study of particle dynamics from the Sun.

• It will study the physics of solar corona and its heating mechanism.

• Diagnostics of the coronal and coronal loops plasma as, Temperature, velocity and density.

• Development, dynamics and origin of CMEs.

• Identify the sequence of processes that occur at multiple layers (chromosphere, base and extended corona) which eventually leads to solar eruptive events.

• Magnetic field topology and magnetic field measurements in the solar corona.

• Drivers for space weather (origin, composition and dynamics of solar wind.

Other Solar Missions by Different Countries

United States

• Parker Solar Probe (August 2018): Touched the Sun’s upper atmosphere, sampled particles and magnetic fields in December 2021

• Solar Orbiter (February 2020): Explores the Sun’s changing space environment

Japan

• Hinotori (ASTRO-A, 1981): Studied solar flares using hard X-rays

• Yohkoh (SOLAR-A, 1991): Studied solar activity

• Hinode (SOLAR-B, 2006): Studied the Sun’s impact on Earth.

Europe

• Ulysses (October 1990): Studied space environment above and below the Sun’s poles

• Proba-2 (October 2001): Part of solar exploratory missions.

• Upcoming: Proba-3 (2024), Smile (2025)

China

• Advanced Space-based Solar Observatory (ASO-S, October 2022): Launched to observe the Sun.

What are Lagrangian Points?

• Lagrangian points, also known as Lagrange points or libration points, are specific locations in space where the gravitational forces of two large bodies, such as a planet and its moon or a planet and the Sun, produce enhanced regions of gravitational equilibrium.

• In these points, the gravitational pull from the two bodies creates a stable or quasi-stable region where a third, smaller object can maintain a relatively constant position relative to the larger bodies.

• There are five primary Lagrangian points, labeled L1 through L5, in a Sun-Earth system.

L1 (Lagrange Point 1)

• It was found by mathematician Joseph Louis Lagrange.

• It is located about 1.5 million kilometers inside Earth's orbit, between the Sun and the Earth.

• The L1 point of the Earth-Sun system gives a clear view of the sun all the time, without any occultation/ eclipses.

• Once the Aditya L1 mission reaches the L1 Lagrange point, it will be injected to a halo orbit. A halo orbit is a type of orbit that allows the satellite to remain in a stable position between the Earth and the Sun.