The Indian Space Research Organization (ISRO) first solar mission — Aditya L1 — has successfully escaped the sphere of Earth's influence. It is now navigating its path towards the Sun-Earth Lagrange Point 1 (L1). This is a major milestone for the Aditya-L1 mission, and for ISRO. It is the second time in succession that ISRO could send a spacecraft outside the sphere of influence of the Earth, the first time being the Mars Orbiter Mission Mangalyaan. Aditya is now heading towards its final destination – Lagrange Point L1 of the Sun-Earth system, ISRO said on Saturday. "The spacecraft has traveled beyond a distance of 9.2 lakh kilometers from Earth, successfully escaping the sphere of Earth's influence. "It is now navigating its path towards the Sun-Earth Lagrange Point 1 (L1). This is the second time in succession that ISRO could send a spacecraft outside the sphere of influence of the Earth, the first time being the Mars Orbiter Mission," the ISRO said in a post on X, formerly Twitter. Earlier on Sept. 19, Aditya L1 had successfully performed a crucial Trans-Lagrangian Point 1 Insertion (TL1I) maneuver that put it on the Sun-Earth L1 point trajectory. Aditya L1, India's first space-based solar mission, was launched from the Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh on Sept. 2. Aditya L1 is India's first space-based observatory class solar mission that will stay approximately 1.5 million km away from Earth. The solar mission will study the outer atmosphere of the sun over the next four years. The Aditya L1 mission reached one step closer to the space at the Lagrange Point 1. Lagrange points are distinct points in space where the gravitational forces of two massive entities balance the centripetal force experienced by a smaller one. As a result, they are perfect for spacecraft since they require little fuel for orbit corrections. Aditya-L1 will be in a 'Halo orbit' around the Sun-Earth L1 point, around 15 lakh km away from Earth. These orbits are three-dimensional and periodic, and they provide out-of-plane motion relative to the primary bodies. The orbit's size means that it can be seen continually from Earth, forming a halo around Lagrange Point. The spacecraft at the Sun-Earth L1 point provide critical early warnings of hazardous space weather events, assisting in the protection of both orbiting space assets and ground-based infrastructure. Despite the low population density at the L1 point and the large distance between spacecraft, ISRO intends to conduct periodic close approach assessments for Aditya L1. The Aditya L1 is scheduled to arrive on Jan. 6, 2024. The solar observatory will monitor the sun with seven specially designed distinct scientific payloads, five of which have been developed by the ISRO. It will do so from its position at a gravitationally stable point in the Earth-sun system called Lagrange point 1 — around 1 million miles (1.5 million kilometers) from Earth — where a spacecraft can remain stable in relation to both bodies. ISRO describes the mission as a "satellite dedicated to the comprehensive study of the sun." Aditya-L1 will investigate the sun's atmosphere, the corona, and its surface, the photosphere. The data it collects could help solve lingering solar mysteries, such as how the corona is considerably hotter than the photosphere despite being around 1,000 miles (1,609 km) further away from the sun's main source of heat, the nuclear fusion that takes place at its core. — Agencies
