It is the first Indian mission dedicated to observing the Sun. Nigar Shaji is the project's director.[8][9][10][11] It was launched aboard a PSLV-XL launch vehicle[1] at 11:50 IST on 2nd September 2023,[12][4][5] 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 the fourth stage at 12:57 IST.[13]
Aditya was conceptualised in January 2008 by the Advisory Committee for Space Sciences (ADCOS).[15][16] It was initially envisaged as a small 400 kg (880 lb), LEO (800 km) satellite with a coronagraph to study the solar corona. An experimental budget of ₹3 crore was allocated for the financial year 2016–2017.[17][18][19] The scope of the mission has since been expanded and it is now planned to be a comprehensive solar and space environment observatory to be placed at Lagrange point L1,[20] so the mission was renamed "Aditya-L1". As of July 2019[update], the mission has an allocated cost of ₹378 crores excluding launch costs.[5]
Aditya L1 in deployed configuration
Name
"Aditya" is named after Surya and the Adityas, the revered Hindu deities representing the Sun. The "L1" designation denotes Lagrange point 1, signifying the precise location situated between the Sun and Earth where the Indian spacecraft is set to embark.[5]
Overview
Lagrange points in the Sun–Earth system (not to scale) – a small object at any one of the five points will hold its relative position.
The Aditya-L1 mission will take around 109 Earth days after launch[21] to reach the halo orbit around the L1 point, which is about 1,500,000 km (930,000 mi) from Earth. The spacecraft will remain in the halo orbit for its planned mission duration while being maintained at a stationkeeping cost of 0.2–4 m/s per year.[22] The 1,500 kg (3,300 lb) satellite carries seven science payloads with diverse objectives, including but not limited to, coronal heating, solar wind acceleration, coronal magnetometry, origin and monitoring of near-UVsolar radiation (which drives Earth's upper atmospheric dynamics and global climate), coupling of the solar photosphere to the chromosphere and corona, 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 that have adverse effects on space and ground-based technologies.[1]
Aditya-L1 will be able to provide observations of the sun's photosphere, chromosphere and corona. In addition, an instrument will study the solar energetic particles' flux reaching the L1 orbit, while a magnetometer payload will measure the variation in magnetic field strength at the halo orbit around L1. These payloads have to 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.[23]
One of the major unsolved issues in the field of solar physics is that the upper atmosphere of the Sun is 1,000,000 K (1,000,000 °C; 1,800,000 °F) whereas the lower atmosphere is just 6,000 K (5,730 °C; 10,340 °F). In addition, it is not understood how exactly 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 may be 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 the close collaboration of various centres of ISRO.[24]
The Aditya-L1, following a flight duration of 63 minutes and 20 seconds, achieved a successful injection into an elliptical orbit around the Earth at 12:54 IST.[25]
The Aditya-L1 is scheduled to undergo a series of four Earth-bound orbital manoeuvres prior to its placement in the transfer orbit towards the Lagrange point L1. Aditya-L1 is projected to reach its designated orbit at the L1 point approximately 127 days following its launch.[26]
Orbit raising burns
First orbit raising burn
On 3 September 2023 the Aditya-L1 performed its first Earth-bound maneuver, raising its orbit to a 245 km (152 mi) into 22,459 km (13,955 mi) orbit.[27]
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Cubesats are smaller. Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
