Mains Daily Question
Feb. 28, 2024

Q.1 What is ‘Aditya L1 Mission’? What do you understand by ‘Lagrange Points’ and describe the principle used for setting Lagrange's Positions? (10M, 150W)

Model Answer

Approach to the answer: 

The question asks about the space based observatory mission, Aditya L1. Further, the concept behind its positioning is asked, so one needs to write about the Lagrange Points and the principle it uses.


We can start by mentioning what the mission is about. Further, the objectives of the mission can be written briefly along with its significance.


As asked in the question, one should start by defining what Lagrange Points are. Here the significance of these points can also be mentioned. Further, a diagram representing all the Lagrange Points along with the advantages/disadvantages of positioning at these points and examples can be written. 


Summarize the importance of the Aditya L1 Mission and the significance of Lagrange Points in space exploration and observation, emphasizing their role in advancing our understanding of the Sun and the cosmos.


Answer: Aditya-L1 is India's inaugural space-based observatory-class solar mission, dedicated to the study of the Sun, particularly its outermost layer, the solar corona. 

It aims to improve our understanding of solar activity and its effects on space weather, which can impact Earth's technology and infrastructure. It will take approximately 125 days to reach the L1 point. The spacecraft is planned to be placed in a halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth system.

Lagrange Points and Principle used:

  • Lagrange points are positions in space where the gravitational forces of two large objects, such as the Earth and the Moon or the Earth and the Sun, produce enhanced regions of attraction and repulsion. These five points result from the interaction of these gravitational forces, and at each point, the gravitational forces of the two large objects, as well as the centripetal force felt by an object in a rotating frame of reference, balance each other out.  This means that a small object, such as a spacecraft, can stay at these points without using much fuel to maintain its orbit.
  • This creates unique locations for spacecraft to position themselves for various purposes, such as Earth observation, space telescopes, or interplanetary travel.
  • There are five Lagrange Points, each with distinct characteristics. These points enable a small mass to orbit in a stable pattern amid two larger masses–i.e. Earth and the Sun or Earth and the Moon.

Lagrange’s Points in the Sun-Earth System

  • L1: L1 is considered the most significant of the Lagrange points for solar observations. A satellite placed in the halo orbit around the L1 has the major advantage of continuously viewing the Sun without any occultation/ eclipses. 
    • Useful for solar observatories like the upcoming Aditya-L1 Mission.


  • L2: Positioned directly 'behind' Earth as viewed from the Sun, L2 is excellent for observing the larger Universe without Earth's shadow interference.
    • The James Webb Space Telescope orbits the Sun near L2.


  • L3: Positioned behind the Sun, opposite Earth, and just beyond Earth's orbit, it offers potential observations of the far side of the Sun.


  • L4 and L5: Objects at L4 and L5 maintain stable positions, forming an equilateral triangle with the two larger bodies.
    • They are often used for space observatories, such as those studying asteroids.


  • However, L1, L2, and L3 points are unstable, meaning that a small perturbation can cause an object to drift away from them. Therefore, satellites orbiting these points need regular course corrections to maintain their positions


The Aditya L1 Mission holds great importance as it aims to enhance our understanding of the Sun and its impact on space weather. It provides valuable insights into solar phenomena, aiding in forecasting space weather events critical for satellite communications and Earth's technology. Lagrange Points are pivotal in space exploration, enabling strategic positioning of observatories like Aditya L1, which offer uninterrupted solar observations.


Subjects : Current Affairs
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