India’s first solar mission, the Aditya-L1 spacecraft, has completed its first halo orbit around the Sun-Earth L1 point on 2 July 2024.
Key points
The Aditya-L1 spacecraft in the halo orbit takes 178 days to complete a revolution around the L1 point.
During its travel in the halo orbit, the Aditya-L1 spacecraft will be subjected to various perturbing forces that will cause it to depart from the targeted orbit.
The Aditya-L1 mission, which is an Indian solar observatory at Lagrangian point L1, was launched on September 2, 2023, and was inserted in its targeted halo orbit on January 6, 2024.
The orbit of Aditya-L1 spacecraft is a periodic Halo orbit which is located roughly 1.5 million km from earth on the continuously moving Sun – Earth line with an orbital period of about 177.86 earth days.
Halo orbit
This Halo orbit is a periodic, three-dimensional orbit at L1 involving Sun, Earth and a spacecraft.
This specific halo orbit is selected to ensure a mission lifetime of 5 years, minimising station-keeping manoeuvres and thus fuel consumption and ensuring a continuous, unobstructed view of sun.
Placing the Aditya-L1 in a halo orbit around L1 point has advantages as compared to placing in a Low Earth Orbit (LEO):
- It provides a smooth Sun-spacecraft velocity change throughout the orbit, appropriate for helioseismology.
- It is outside of the magnetosphere of Earth, thus suitable for the “in situ” sampling of the solar wind and particles.
- It allows unobstructed, continuous observation of the Sun, and view of earth for enabling continuous communication to ground stations.
