ISRO launches Aditya L1 in elliptical orbit – on way to a 125-day voyage to Sun



The Indian Space Research Organisation (ISRO) launched the Polar Satellite Launch Vehicle-C57/Aditya-L1 Mission from the Satish Dhawan Space Centre in Andhra Pradesh on Saturday, September 2.

The complex launch procedure took more than an hour to complete owing to the configurations required for the spacecraft to achieve a precise elliptical orbit that will eventually slingshot it towards the Sun. The fourth stage of the PSLV was fired two separate times to take the primary payload of the mission to the precise place for orbit insertion. ISRO’s PSLV will carry the satellite on a 125-day voyage to study the Sun.

Aditya-L1 is a satellite dedicated to the comprehensive study of the Sun. It has 7 distinct payloads developed, all developed indigenously. Five by ISRO and two by Indian academic institutes in collaboration with ISRO.

The scientists said that Helio physicists from not just India but the world are awaiting the results of the mission. ISRO is only the third after the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) to place an observatory at the L1 point between the Earth and the Sun. “The Sun is a giant sphere of gas and Aditya L1 would study the outer atmosphere of the Sun. Aditya L1 will neither land on the Sun nor approach the Sun any closer,” ISRO said on Friday. The main objective of the mission is to get a deeper understanding of the star closest to us and how its radiation, heat, flow of particles, and magnetic fields affect us.

Dr Sanaka Subramanian, the scientist leading the Aditya L1 mission, said that at the time when the mission was conceived it was ensured that it would provide a unique set of data that has not been provided by any other mission so far. He said that the seven payloads onboard the Aditya L1 will help study the Sun comprehensively — it carries instruments that can see the Sun in multiple wavelengths such as X-ray, UV, and visible light; it can study the radiation, particles, and magnetic fields emitted by the Sun; it can also study various phenomenon in different directions.

While Aditya in Sanskrit means the Sun, L1 refers to Lagrange Point 1 of the Sun-Earth system. The L1 is a location in space where the gravitational forces of the Sun and Earth, are in equilibrium. This allows an object placed there to remain relatively stable.

During its stay in Earth-bound orbits for 16 days, it will undergo 5 maneuvers to gain the necessary velocity for its journey. Then Aditya-L1 will undergo a Trans-Lagrangian1 insertion maneuver, marking the beginning of its 110-day trajectory to the destination around the L1 Lagrange point. Upon arrival at the L1 point, another maneuver will bind Aditya-L1 to an orbit around L1, a balanced gravitational location between the Earth and the Sun. Aditya-L1 will stay approximately 1.5 million km away from Earth. The satellite will spend its whole mission life orbiting around L1 in an irregularly shaped orbit in a plane roughly perpendicular to the line joining the Earth and the Sun.

“The strategic placement at the L1 Lagrange point ensures that Aditya-L1 can maintain a constant, uninterrupted view of the Sun. This location also allows the satellite to access solar radiation and magnetic storms before they are influenced by Earth’s magnetic field and atmosphere. Additionally, the L1 point’s gravitational stability minimizes the need for frequent orbital maintenance efforts, optimizing the satellite’s operational efficiency,” the ISRO said in a statement.

After the precise injection into the orbit, ISRO Chairperson S Somanath said: “Congratulations, the Aditya L1 spacecraft is injected in an elliptical orbit very precisely in a very unique mission mode, with the upper stage of the PSLV taking two burns for the primary satellite for the first time.”

Mission Director Biju S R added: “The orbital requirements given by the satellite team were very challenging. We have gone for a new mission descent strategy. We have gone through numerous simulations to validate this and this is the proof. With this, the capability of PSLV has increased manifold to venture into new and challenging missions.”

“Congratulations India. Congratulations ISRO,” said Union Minister of State for the Department of Space Dr Jitendra Singh who was present in the mission control complex during the launch.



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