Lagrangian Points and the Aditya-L1 Mission
Context:
India's first dedicated space-based solar mission, Aditya-L1, is positioned at the Sun-Earth Lagrangian L1 location
From this vantage point, its Visible Emission Line Coronagraph (VELC) payload has been used by scientists from the Indian Institute of Astrophysics (IIA) and NASA to study crucial parameters of a coronal mass ejection (CME)
What are Lagrangian Points?
Lagrangian points are positions in space where the gravitational pull of two large masses (like the Sun and Earth) precisely equals the centripetal force required for a small object (like a spacecraft) to move with them.
They are named in honor of Italian-French mathematician Josephy-Louis Lagrange
Spacecraft can use these points to reduce the fuel consumption needed to remain in position
The Five Points:
There are five such points in any two-body system
L1, L2, and L3:
These three points lie along the line connecting the two large masses.
They are unstable on a timescale of approximately 23 days
Thereby requiring satellites to undergo regular course corrections
L4 and L5:
These points form the apex of two equilateral triangles with the large masses at their vertices.
Orbits at L4 and L5 are stable.
Objects found here are often called Trojans
Aditya-L1 Mission at L1
The Aditya-L1 observatory is placed at the L1 point of the Earth-Sun system
Strategic Advantage of L1:
L1 location provides a sustained, uninterrupted view of the sun 24 hours a day (as the sun never sets from this point)
It allows the VELC instrument to observe CMEs very close to the sun's visible surface for the first time
Other Missions:
The L1 point is also home to the Solar and Heliospheric Observatory Satellite (SOHO).
The L2 point is used for astronomy
For example, James Webb Space Telescope
It allows a clear view of deep space.