Aditya-L1 Mission: Aditya L1, India's first space-based mission to study the Sun, got a "send-off" from the Earth as ISRO successfully performed the Trans-Lagrangian 1 Insertion (TL1I) manoeuvre in the early hours of Tuesday (September 19), the space agency said.
According to the Indian Space Research Organisation (ISRO), the TL1I manoeuvre marks the beginning of Aditya-L1’s 110-day journey towards the L1 Lagrange point, a balanced gravitational location between the Earth and the Sun.
This is the fifth consecutive time the ISRO has successfully transferred an object on a trajectory toward another celestial body or location in space.
'Off to Sun-Earth L1 point'
"Off to Sun-Earth L1 point! The Trans-Lagrangean Point 1 Insertion (TL1I) manoeuvre is performed successfully. The spacecraft is now on a trajectory that will take it to the Sun-Earth L1 point. It will be injected into an orbit around L1 through a manoeuvre after about 110 days. This is the fifth consecutive time ISRO has successfully transferred an object on a trajectory toward another celestial body or location in space," ISRO said in a post on X.
ISRO's Polar Satellite Launch Vehicle (PSLV-C57) had on September 2 successfully launched Aditya-L1 from the Second Launch Pad of Satish Dhawan Space Centre, Sriharikota. Aditya-L1 is the first Indian space-based observatory that will study the Sun from a halo orbit around the first Sun-Earth Lagrangian point (L1), which is located roughly 1.5 million km from the Earth.
The Sun is a giant sphere of gas, and Aditya-L1 would study the outer atmosphere of the Sun. It will neither land on the Sun nor approach the Sun any closer.
Another manoeuvre will be performed on arrival at L1 point
Following the launch, Aditya-L1 underwent four Earth-bound manoeuvres on September 3, 5 ,10 and 15 respectively, during which it gained the necessary velocity for its further journey to L1. Upon arrival at the L1 point, another manoeuvre binds Aditya-L1 to an orbit around L1.
Aditya-L1 is expected to arrive at the intended orbit at the L1 point after about 127 days, ISRO had said soon after the launch.
Aditya-L1 carries seven scientific payloads indigenously developed by ISRO and national research laboratories including Indian Institute of Astrophysics (IIA), Bengaluru, and Inter University Centre for Astronomy and Astrophysics (IUCAA), Pune. The payloads are to observe the photosphere, chromosphere and the outermost layers of the Sun (the corona) using electromagnetic and particle and magnetic field detectors.
Scientific data collection has started
ISRO on Monday (September 18) said that Aditya L1 has commenced collecting scientific data. The sensors of the Supra Thermal and Energetic Particle Spectrometer (STEPS) instrument have begun measuring supra-thermal and energetic ions and electrons at distances greater than 50,000 km from Earth.
STEPS comprises six sensors, each observing in different directions and measuring supra-thermal and energetic ions ranging from 20 keV/nucleon to 5 MeV/nucleon, in addition to electrons exceeding 1 MeV. These measurements are conducted using low and high-energy particle spectrometers. The data collected during Earth’s orbits helps scientists to analyse the behaviour of particles surrounding the Earth, especially in the presence of the magnetic field of Earth.
STEPS was activated on September 10, 2023, at a distance greater than 50,000 km from Earth. This distance is equivalent to more than 8 times the Earth's radius, placing it well beyond Earth's radiation belt region. After completing the necessary instrument health checks, data collection continued until the spacecraft had moved farther than 50,000 km from Earth.
Each unit of STEPS is operating within normal parameters. A figure displays measurements depicting variations in the energetic particle environment within Earth's magnetosphere, collected by one of the units. These STEPS measurements will persist during the cruise phase of the Aditya-L1 mission as it progresses toward the Sun-Earth L1 point. They will continue once the spacecraft is positioned in its intended orbit. Data collected around L1 would provide insights into the origin, acceleration, and anisotropy of solar wind and space weather phenomena. STEPS was developed by the Physical Research Laboratory (PRL) with support from the Space Application Centre (SAC) in Ahmedabad.
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