Introduction

The Indian Space Research Organisation (ISRO) has achieved a significant milestone by placing the Aditya-L1 spacecraft in a halo orbit around the Lagrangian point (L1).
Launched on September 2, 2023, Aditya-L1 reached the L1 point on January 6, after a 127-day journey covering 1.5 million km.

What is a Halo Orbit?

Halo orbits are three-dimensional, periodic orbits around Lagrange points in a two-body system like Earth-Sun or Earth-Moon.
It is commonly linked with L1, L2, and L3 Lagrange points, where the gravitational forces of two large bodies and centrifugal force balance each other.
It provides a stable line of sight to Earth and the Sun, beneficial for continuous communication and solar power.
Unlike typical two-dimensional orbits, halo orbits form a 3D loop, resembling a halo around Lagrange points.
These orbits, especially around L1 and L2 points, require periodic adjustments for a spacecraft to maintain its trajectory.
It offers energy-efficient positions in space due to balanced gravitational forces, requiring minimal propulsion for orbit maintenance.
James Webb Space Telescope utilizes a halo orbit around the Earth-Sun L2 point for a stable observation position.

Orbit Characteristics: Aditya-L1 is in a periodic halo orbit around L1, approximately 1.5 million km from Earth, with an orbital period of about 177.86 days.
Mission Life and Goals: With a mission life of five years, Aditya-L1 aims to study the sun’s photosphere, chromosphere, and corona, along with in-situ studies of particles and fields at L1.
Continuous Solar Observation: The satellite’s position allows for uninterrupted solar observation, crucial for understanding solar activities and space weather dynamics.

Lagrange Points Explained: Lagrange Points are positions in space where a small object can maintain its position relative to two larger bodies due to the gravitational balance.
L1 Point Advantage: The L1 point, located about 1.5 million km from Earth, offers continuous solar viewing without occultation or eclipse, providing a strategic advantage for solar observation.

Launch and Initial Orbits: Following its launch, ISTRAC conducted four earth-bound maneuvers to position Aditya-L1 in progressively higher orbits.
Trans-Lagrangian1 Insertion: The spacecraft underwent a crucial manoeuvre on September 19, marking the start of its 110-day journey to L1.

Understanding Solar Dynamics: Studying the sun is crucial for comprehending its energy production, temperature variations, and radiation emissions.
Monitoring Solar Activities: Continuous monitoring of solar flares and coronal mass ejections is vital for predicting space weather and mitigating its impact on space-reliant technologies.

Unprecedented Solar Study: Aditya-L1’s unique position and advanced instruments enable an unparalleled study of the sun, contributing significantly to our understanding of solar phenomena.
ISRO’s Achievement: This successful mission underscores ISRO’s expertise in navigating complex space missions and reinforces India’s position as a leading player in space exploration and research.