It is the first Indian mission dedicated to observing the Sun. Nigar Shaji is the project's director.[7][8][9][10] It was launched aboard a PSLV-XL launch vehicle[1] at 11:50 IST on 2 September 2023,[11][3][4] 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.[12]
Mission objectives
Aditya L1's main science objectives are:
Dynamics of Solar Upper Atmosphere (Chromosphere and Corona)
Studies of Chromospheric and Coronal heating, Physics of Partially ionised Plasma, Initiation of Coronal Mass Ejections (CMEs) and Exchanges of Flares
Observation of In-situ Particle and Plasma Environment, providing data for the Study of Particle Dynamics from the Sun
Physics of Solar Corona and its Heat Mechanism
Determination of Coronal and Coronal Loop Plasma: Temperature, Velocity, Density, Development, Dynamics and Origin of the CMEs
Determination of the sequence of processes at multiple layers (Chromosphere, Base and Extended Corona) that lead to Solar eruptive events
Magnetic Field Topology and Measurement in the Solar Corona. NM
Drivers for Space Weather (Origin, Composition and Dynamics of Solar Wind[13]
History
Aditya-L1 in stowed configuration
Aditya was conceptualised in January 2008 by the Advisory Committee for Space Research[dubious – discuss]. 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.[14][15][16] 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,[17] so the mission was renamed "Aditya-L1". As of July 2019[update], the mission has an allocated cost of ₹378 crores excluding launch costs.[4]
Aditya L1 in deployed configuration
Name
"Aditya" is derived from Surya, the revered Hindu deity 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.[4]
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[18] 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 maintained at a stationkeeping cost of 0.2 – 4 m/s per year.[19] The 1,500 kg (3,300 lb) satellite carries seven science payloads with diverse objectives, including but not limited to, the 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 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 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 on the original Aditya mission concept.[20]
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) hot 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 shorter as well as on 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.[21]
The Aditya-L1 mission holds the promise of significantly advancing our understanding of the Sun's behavior and its interactions with Earth and the space environment. The planned observations and data collection from this mission could lead to several groundbreaking discoveries and insights in the field of solar and heliophysics:
Coronal Heating Mechanism:[22] One of the central puzzles in solar physics is the coronal heating problem - why the Sun's corona is much hotter than its surface. Aditya-L1's instruments, particularly the Solar Ultraviolet Imaging Telescope (SUIT) and the Visible Emission Line Coronagraph (VELC), will enable detailed studies of the corona's dynamics and composition. By closely examining the behavior of the corona, scientists hope to unravel the mechanisms responsible for heating this outer layer of the Sun.
Space Weather Prediction:[23] Understanding the Sun's behavior is crucial for predicting space weather events, which can have significant impacts on Earth's technology and infrastructure. The mission's data will provide insights into the processes that lead to solar flares, coronal mass ejections (CMEs), and solar energetic particle (SEP) events. These insights can contribute to more accurate forecasting of space weather phenomena and their potential effects on communication systems, satellites, and power grids.
Solar Wind and Magnetic Field Studies: Aditya-L1's instruments like the Aditya Solar wWnd Particle Experiment (ASPEX) and the Magnetometer, will offer a comprehensive view of the solar wind's properties and the interplanetary magnetic field. This data will help refine models of the solar wind's behavior and its interaction with Earth's magnetosphere, shedding light on the dynamics of this critical space environment.
Understanding Earth's Climate: The Sun's activity can influence Earth's climate over long timescales. Aditya-L1's observations of near-UV solar radiation and its impact on Earth's upper atmosphere can contribute to understanding how solar variability might affect Earth's climate patterns. This could provide valuable information for climate researchers seeking to differentiate between natural and anthropogenic factors driving climate change.
Comprehensive Solar Atmosphere Imaging: The suite of instruments on Aditya-L1 will provide multi-wavelength observations of the Sun's atmosphere, from the photosphere to the corona. These simultaneous observations will allow scientists to trace the flow of energy and matter between different layers, offering insights into the complex processes that govern the Sun's behavior.
Trajectory of PSLV-C57/Aditya L1 MissionOrigin and Dynamics of CMEs: Coronal mass ejections are powerful and potentially disruptive solar events. Aditya-L1's observations of the initiation and evolution of CMEs will contribute to our understanding of their origins and behavior, potentially leading to improved models for predicting their occurrence and effects.
On the morning of the launch, several thousand individuals congregated at the viewing gallery adjacent to the launch site to witness the liftoff. Simultaneously, it was broadcast live on national television, with commentators characterizing it as a "remarkable" launch.[4]
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. This orbit has dimensions of 23,500 x 19,500 km.[citation needed]
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.[24]
Orbit raising burns
First orbit raising burn
On 3 September 2023 the Aditya-L1 performed its first earth-bound maneuver, raising its orbit from a 245 km (152 mi) orbit to a 22,459 km (13,955 mi) orbit.[25]
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
