On September 2nd, 2023, at 11.50 hrs, the Polar Satellite Launch Vehicle (PSLV-C57) successfully launched the Aditya-L1 spacecraft, from the Second Launch Pad of Satish Dhawan Space Centre (SDSC), Sriharikota with Aditya-L1 being the first Indian space based observatory to study the Sun from a halo orbit around first Sun-Earth Lagrangian point (L1), which is located roughly 1.5 million km from earth.
After a flight duration of 63 minutes and 20 seconds, Aditya-L1 spacecraft was successfully injected into an elliptical orbit of 235x19500 km around the Earth. Aditya-L1 is expected to arrive the intended orbit at the L1 point after about 127 days.
Why studying the Sun?
The sun being the nearest star, can be studied in so much detail to learn much more about stars in our Milky away even learn much more about the origin of the stars and the galaxy, along with stars of various other galaxies. Sun being a huge star shows various eruptive phenomena and release immense amount of energy into the solar system. Thus if such eruptions are directed towards the earth it might cause various disturbances i near earth environment. Various spacecraft and communication systems can be targeted to such phenomena therefore a prior warning and study can help taking correct measures. Also, extreme magnetic and thermal field of sun can provides a good natural laboratory for studies that cannot be conducted such well directly from labs.
Why studying Sun from L1?
Aditya in Sanskrit means the Sun and L1 refers to Lagrange Point 1 of the Sun-Earth system. Basically, L1 is a location in space where the gravitational forces of two celestial bodies, here the Sun and Earth, are in equilibrium. Thus t-he satellite remains stable with respect to both the celestial bodies.
The spacecraft carries seven scientific payloads for systematic study of the Sun.
Remote Sensing Payloads consist of:
- Visible Emission Line Coronagraph(VELC) for Corona/Imaging & Spectroscopy.
- Solar Ultraviolet Imaging Telescope (SUIT) for Photosphere and Chromosphere Imaging- Narrow & Broadband.
- Solar Low Energy X-ray Spectrometer (SoLEXS) for Soft X-ray spectrometer: Sun-as-a-star observation.
- High Energy L1 Orbiting X-ray Spectrometer(HEL1OS) for Hard X-ray spectrometer: Sun-as-a-star observation.
In-situ Payloads consist of :
-Aditya Solar wind Particle Experiment(ASPEX) for Solar wind/Particle Analyzer Protons & Heavier Ions with directions.
-Plasma Analyser Package For Aditya (PAPA) for Solar wind/Particle Analyzer Electrons & Heavier Ions with directions.
-Advanced Tri-axial High Resolution Digital Magnetometers for In-situ magnetic field (Bx, By and Bz) study.
All payloads are developed in collaboration with various ISRO centers and scientific institutes including Indian Institute of Astrophysics (IIA), Bengaluru and Inter University Centre for Astronomy & Astrophysics (IUCAA), Pune. Aditya-L1 will stay approximately 1.5 million km away from Earth, directed towards the Sun, that is about 1% of the Earth-Sun distance.
Major Scientific Objectives:
• Study of Solar upper atmospheric (chromosphere and corona) dynamics.
• Understanding the Coronal Heating and Solar Wind Acceleration.
• Understanding initiation of Coronal Mass Ejection (CME), flares and near-earth space weather.
• To understand coupling and dynamics of the solar atmosphere.
• To understand solar wind distribution and temperature anisotropy.
• Magnetic field topology and magnetic field measurements in the solar corona .
• Observe the in-situ particle and plasma environment providing data for the study of particle dynamics from the Sun.
Aditya-L1 is supposed to stay in Earth-bound orbits for 16 days, during which it undergoes 5 maneuvres to gain the required velocity for its further journey. Subsequently, Aditya-L1 undergoes a Trans-Lagrangian1 insertion maneuvre, marking the beginning of its 110-day trajectory to the destination around the L1 Lagrange point. Finally upon arrival at the L1 point, another maneuvre binds Aditya-L1 to an orbit around L1.