ISRO's First Solar Mission Launches Successfully, Mission Details

The Aditya-L1 mission was launched from the Sriharikota spaceport, ISRO's primary launch facility, shortly before noon on Saturday, September 2. An hour later, the spacecraft was placed into an Earth orbit

Srajan Girdonia
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Just a day after the historic launch of the Aditya-L1 spacecraft, India's first mission dedicated to studying the Sun, the Indian Space Research Organisation (ISRO) reported that the satellite is in good health and the first orbit-raising manoeuvre has been executed successfully. The mission, aimed at gaining deeper insights into the Sun's behaviour and its impact on Earth, is off to a promising start.

A Healthy Satellite

ISRO confirmed that the Aditya-L1 satellite is operating nominally, signalling a positive beginning for the mission. The critical first Earth-bound manoeuvre was flawlessly executed from the ISRO Telemetry, Tracking, and Command Network (ISTRAC) in Bengaluru.

The newly achieved orbit measures 245 km x 22,459 km. ISRO is now preparing for the next manoeuvre scheduled for 0300 Hours IST on September 5, marking another significant step forward in the Aditya-L1 mission.

The Launch and Initial Journey

The Aditya-L1 mission was launched from the Sriharikota spaceport, ISRO's primary launch facility, shortly before noon on Saturday September 2. An hour later, the spacecraft was placed into an Earth orbit with dimensions of 235 km x 19,500 km.

Over the upcoming days, Aditya-L1 will continue its journey around Earth, progressively raising its orbit and gathering momentum. This initial phase is crucial as it prepares the satellite for its four-month voyage to the Lagrange-1 point within the Earth-Sun system. Located approximately 1.5 million kilometres from Earth, this vantage point will enable Aditya-L1 to observe the Sun and conduct various experiments.

Aditya L1 Mission Cost and Objectives

The Aditya-L1 solar mission reportedly has a budget of over ₹300 crores. Among its objectives are the observation of the Solar upper atmosphere, including the chromosphere and corona, as well as studying the in-situ particle and plasma environment. The mission will provide crucial data for understanding particle dynamics from the Sun and the physics of solar corona heating.

Furthermore, Aditya-L1 aims to investigate the drivers of space weather, magnetic field topology, magnetic field measurements in the solar corona, and the dynamics of solar wind. With seven payloads on board, including four for remote sensing and three for in-situ observations, the mission promises to significantly contribute to solar research.

PSLV's Remarkable Milestone

Notably, the heavier version of the Polar Satellite Launch Vehicle (PSLV) rocket achieved a significant milestone during this mission. For the first time ever, the fourth stage of the PSLV was fired twice to precisely insert the Aditya-L1 spacecraft into its intended orbit.

During the fourth stage of firing and the coasting phase between burns, there were two periods totalling nearly 27 minutes when the satellite was out of sight. However, the data was successfully acquired by a ship-based station in the Bay of Bengal and later by the Kourou ground station in French Guiana, ensuring the mission's progress.

Seven Payloads, One Mission

The Aditya-L1 spacecraft carries seven essential payloads, making it an observatory-class satellite. The primary objective of this mission is to gain a deeper understanding of the Sun's radiation, heat, particle flows, and magnetic fields and their effects on Earth. Conducting these studies from space eliminates the distortions caused by Earth's atmosphere, magnetic field, and dust particles.

A scientist from ISRO explained that launching the mission in September required the satellite to travel a longer path to achieve the necessary insertion angle. This decision was made to ensure the spacecraft's precise orbit, akin to navigating from the front yard when originally planning to leave from the backyard.

The Journey Ahead

ISRO anticipates that Aditya-L1's journey from launch to the Lagrange point 1 (L1) will take roughly four months. At L1, Aditya-L1 will enter a halo orbit around the Sun-Earth system's equilibrium point. This unique orbital position is made possible by the gravitational forces between two large bodies, the Sun and Earth, which create a region of equilibrium. Utilizing this point will reduce the satellite's fuel consumption, allowing it to focus on its scientific objectives more efficiently.

The Aditya-L1 mission marks a significant milestone in India's space exploration endeavours, offering the nation valuable insights into the Sun's behaviour and its impact on Earth. As the mission progresses, the global scientific community eagerly awaits the wealth of data and discoveries that Aditya-L1 will bring to light.