Introduction
In the wake of the historic success of Chandrayaan 3, the Indian Space Research Organization (ISRO) is embarking on another groundbreaking mission: Aditya L1, India’s first mission dedicated to studying the Sun. Unlike Chandrayaan’s lunar landing, Aditya L1 will observe the Sun from a distance, positioning itself at the Lagrange point L1. This article delves into the mission’s details and significance.
Lagrange Points: The Key to Stability

Lagrange points are unique positions in space where the gravitational forces of two celestial bodies balance out. In the case of the Sun and Earth, there are five Lagrange points, with L1 being the focus of Aditya L1. These points offer spacecraft unparalleled stability, allowing for long-duration missions and continuous observations of both the Earth and the Sun without being eclipsed by either.
Aditya L1’s Mission Objectives
Aditya L1’s primary mission is to study the three topmost layers of the Sun: the Photosphere, Chromosphere, and Corona. These layers present intriguing mysteries for scientists, including the stark temperature differences between the Sun’s core, surface, and Corona.
Understanding the Sun’s Layers

- The Sun’s core is the site of nuclear fusion reactions, where hydrogen and helium gases are converted into energy, generating sunlight and heat. Temperatures in the core can reach up to 15 million degrees Celsius.
- Surrounding the core is the radiative zone, accounting for 70% of the Sun’s radius.
- The convective zone follows, transferring energy through convection.
- The Photosphere, often called the Sun’s “surface,” has a relatively cooler temperature of 5,500°C.
- Above the Photosphere lies the Chromosphere, where temperatures rise from 6,000°C to 20,000°C.
- Beyond the Chromosphere, the Transition Region and the outermost layer, the Corona, with temperatures soaring to 1-3 million degrees Celsius.
Instruments on Aditya L1
Aditya L1 carries seven instruments, or payloads, to fulfill its mission:
- Visible Emission Line Coronagraph (VELC): VELC is designed to provide insights into the Sun’s Corona layer and Coronal Mass Ejections (CMEs). It captures emissions in visible light, allowing scientists to monitor and study these solar phenomena in detail.

2. Solar Ultraviolet Imaging Telescope (SUIT): SUIT specializes in capturing high-resolution images of the Sun’s photosphere and chromosphere using the ultraviolet spectrum. These images offer crucial data for understanding solar activities and dynamics.

3. Solar Low Energy X-ray Spectrometer (SOLEXS) and High Energy L1 Orbiting X-ray Spectrometer (HEL1OS): SOLEXS and HEL1OS work in tandem to study X-rays emitted during solar flares. They provide valuable information about the Sun’s high-energy processes, aiding in predicting and understanding solar eruptions.


4. Aditya Solar Wind Particle Experiment (ASPEX) and Plasma Analyzer Package for Aditya (PAPA): ASPEX and PAPA focus on investigating the solar wind, a stream of charged particles emanating from the Sun. These instruments analyze the composition and properties of solar wind, helping scientists better comprehend its impact on our solar system.


5. Magnetometer (MAG): MAG plays a crucial role in measuring magnetic fields at the Lagrange point L1. By monitoring these magnetic fields, scientists can gain insights into the complex interplay between the Sun’s magnetic forces and their effects on space weather and Earth’s environment.


Comparative Missions

Aditya L1 joins a group of missions dedicated to understanding the Sun, including NASA’s Parker Solar Probe and Solar Orbiter. These missions collectively seek to unravel the Sun’s secrets, particularly related to harmful solar radiation.
Conclusion
Aditya L1’s mission to study the Sun from afar at the L1 Lagrange point holds the promise of shedding light on the mysteries of our solar system’s central star. With its array of instruments, it aims to decipher the Sun’s complex layers and phenomena, contributing to our understanding of this vital celestial body.