Aditya-L1 - An Observatory Class Mission: Spacecraft, Mission, and Operations

Abstract

Aditya-L1 is an observatory class mission designed and developed by the Indian Space Research Organisation (ISRO) to study the Sun and the inner heliosphere. Aditya-L1, currently orbiting around the first Lagrange point L1, is in a periodic halo orbit located approximately at 1.5 million km from Earth on the Sun–Earth line (about 1% of the Sun-Earth distance and closer to Earth). The orbital parameters of Aditya-L1 around L1 are Ax = 208,951 km, Ay = 670,024 km and Az = 120,000 km, where Ax, Ay and Az are semi-diameters of the orbit with an orbital period of 177.86 days. The primary objective of the Aditya-L1 mission is to understand the coronal and chromospheric dynamics of the Sun along with its influence on the heliosphere, especially at the L1 location. To achieve these goals, the spacecraft is configured to accommodate seven payloads of which four are remote sensing and three are in situ experiments. The scientific payloads are designed and developed by various Indian Research Institutes in close collaboration with different ISRO centers. The spacecraft is configured with the modified Mars orbiter mission (MOM) bus and is a three-axis stabilized spacecraft with a lift of mass of 1480.73 kg and power generation of ≈ 1820 W. Pointing stability will be better than 15 arcsec as required by the coronagraph payload. Aditya-L1 payload produces around 240 Gbits of science data per day (≈ 90% data is from the imaging payloads). Planning, coordination, and operation of the spacecraft and the scientific payloads are conducted from ISRO telemetry, tracking, and command network in Bengaluru, India. Aditya-L1 was launched on board the Polar Satellite Launch Vehicle (PSLV C57) at 11:50 Indian standard time (IST) from the second launch pad of the Satish Dhawan Space Centre (SDSC), Sriharikota, India on 2 September 2023. It was inserted at the L1 point on 6 January 2024, at 4:17 pm IST. The spacecraft, mission, and operation aspects of the Aditya-L1 spacecraft are discussed in this paper.