Aditya-L1 (/ɑːd̪it̪jə/)(from Sanskrit: Aditya, "sun" and L1, "Lagrange 1 Point") a coronagraphy spacecraft to study the solar atmosphere, designed and developed by the Indian Space Research Organisation (ISRO) and various other Indian research institutes. It will be orbiting at about 1.5 million km from Earth in a halo orbit around the L1 Lagrange point between the Earth and the Sun where it will study the solar atmosphere, solar magnetic storms, and their impact on the environment around the Earth.
It is the first Indian mission dedicated to observing the Sun. Nigar Shaji is the project's director. Aditya-L1 was launched aboard the PSLV C57 at 11:50 IST on 2 September 2023, ten days after the successful landing of ISRO's Moon mission, Chandrayaan-3. It successfully achieved its intended orbit nearly an hour later, and separated from its fourth stage at 12:57 IST. It is projected to reach its designated orbit at the L1 point approximately 127 days after its launch.
Science objectives
The main objectives of Aditya L1 are: To observe the dynamics of the Sun's chromosphere and corona: To study chromospheric and coronal heating, the physics of partially ionised plasma, of coronal mass ejections (CMEs) and their origins, of the coronal magnetic field and heat transfer mechanisms, and flare exchanges To observe of the physical particle environment around its position To determine the sequence of processes in multiple layers below the corona that lead to solar eruptions To study space weather, and the origin, composition and dynamics of solar wind
History
Aditya was conceptualised in January 2008 by the Advisory Committee for Space Sciences (ADCOS). It was initially envisaged as a small satellite in a Low Earth Orbit (800 km) with a coronagraph to study the solar corona. An experimental budget of was allocated for the financial year 2016–2017. The scope of the mission has since been expanded and it became a comprehensive solar and space environment observatory to be placed at Lagrange point L1, hence the mission was renamed "Aditya-L1". , the mission has an allocated cost of excluding launch costs.
Overview
The Aditya-L1 mission will take around 109 Earth days after launch to reach the halo orbit around the L1 point, which is about from Earth. The spacecraft is planned to remain in the halo orbit for its mission duration while being maintained at a stationkeeping Δv of 0.2–4 m/s per year. The satellite carries seven science payloads with various objectives, including instruments to measure coronal heating, solar wind acceleration, coronal magnetometry, origin and monitoring of near-UV solar radiation (which drives Earth's upper atmospheric dynamics and global climate), coupling of the solar photosphere to the chromosphere and corona, and in-situ characterisations of the space environment around Earth by measuring energetic particle fluxes and magnetic fields of the solar wind, and solar magnetic storms.
Aditya-L1 will provide observations of the sun's photosphere, chromosphere and corona. Its scientific payloads must be placed outside the interference from the Earth's magnetic field and hence could not have been useful in the low Earth orbit as proposed in the original Aditya mission concept.
One of the major unsolved problems in the field of solar physics is coronal heating. The upper atmosphere of the Sun has a temperature of whereas the lower atmosphere is just . In addition, it is not understood exactly how the Sun's radiation affects the dynamics of the Earth's atmosphere on a shorter as well as a longer time scale. The mission will obtain near-simultaneous images of the different layers of the Sun's atmosphere, which will reveal the ways in which energy is channeled and transferred from one layer to another. Thus, the Aditya-L1 mission will enable a comprehensive understanding of the dynamical processes of the Sun and address some of the outstanding problems in solar physics and heliophysics.
Payloads
The instruments of Aditya-L1 are tuned to observe the solar atmosphere, mainly the chromosphere and corona. In-situ instruments will observe the local environment at L1. There are seven payloads on-board, with four for remote sensing of the Sun and three for in-situ observation. The payloads have been developed by different laboratories in the country with close collaborations of various ISRO centres.