The Indian Space Research Organisation (ISRO) has successfully placed India’s Aditya-L1 space probe into a halo orbit around the Sun for a five-year study of the Sun’s activities. Aditya-L1 has been placed in a halo orbit at the Sun-Earth Lagrange’s Point 1 (L1), which is located 1.5 million kilometers away from Earth. The space probe, developed and realized by ISRO, will study various phenomena related to the Sun, such as coronal heating and Coronal Mass Ejection (CME). It will also study space weather and the propagation of particles and fields in the interplanetary medium.
The trajectory of the Aditya-L1 space probe was carefully planned to ensure precise navigation and control. The final phase of the maneuver involved a brief firing of control engines, which placed the probe into a periodic halo orbit. This orbit offers a continuous and unobstructed view of the Sun. The L1 location offers several benefits, including a smooth change in velocity suitable for studying helioseismology and ‘in-situ’ sampling of solar wind and particles. Additionally, being outside Earth’s magnetosphere allows for uninterrupted communication with ground stations.
The Aditya-L1 spacecraft carries payloads developed by the Indian Institute of Astrophysics (IIA), Bengaluru, Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, and ISRO. The payloads include the Visible Emission Line Coronagraph (VELC) for studying solar corona and coronal mass ejections, the Solar Ultra-violet Imaging Telescope (SUIT) for imaging the Solar Photosphere and Chromosphere, the Solar Low Energy X-ray Spectrometer (SoLEXS) and High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) for studying X-ray flares from the Sun, the Aditya Solar wind Particle EXperiment (ASPEX) and Plasma Analyser Package for Aditya (PAPA) for studying the solar wind and energetic ions, and the Magnetometer (MAG) for measuring interplanetary magnetic fields.
To ensure compliance with the halo orbit insertion (HOI) parameters, ISRO conducted at least two trajectory corrective maneuvers (TCMs) in October and December 2023. All payloads underwent thorough testing during the pre-commissioning phase, confirming their satisfactory performance. The Aditya-L1 spacecraft was launched on September 2, 2023, and initially placed into an elliptical parking orbit. It gradually increased its orbital size through a series of liquid engine burns during the Earth orbit phase, culminating in the trans-L1 injection (TL1I) maneuver. This maneuver set the spacecraft on its path towards L1. Finally, the HOI maneuver placed the Aditya-L1 probe into the desired halo orbit around the Sun.
Studying the Sun is crucial as it is the nearest star and the largest object in the solar system, and its activities significantly impact Earth. Solar wind, composed mostly of high-energy protons, constantly flows from the Sun and fills the entire known solar system. The solar magnetic field present in the solar wind affects the nature of space. Solar events like Coronal Mass Ejections (CME) can cause magnetic disturbances near Earth that can affect the functioning of space assets. By studying the Sun and space weather, scientists can better understand and predict such events, which is vital for protecting space assets and ensuring astronaut safety.
