Aditya-L1 sets off ahead of its date with the Sun

SRIHARIKOTA: India on Saturday successfully launched its first observation mission to the Sun. Its Polar Satellite Launch Vehicle placed the Aditya-L1 satellite in a low earth orbit from where it will commence its four-month journey to the Lagrange Point 1 (L1), an equilibrium point between the gravitational forces of the Sun and Earth, which allows the spacecraft to hover. This comes within a week of India becoming the first nation to land near the Moon’s south pole.

The PSLV rocket with a lift-off mass of 321 tonnes blasted off from the second launch pad in Satish Dhawan Space Centre (SDSC-Shar) here at 11.50 AM. It was PSLV’s 59th flight and 25th mission with an XL configuration. The rocket, which is India’s workhorse, has a whopping 95 per cent success rate. 

ISRO chairman S Somanath said: “The Aditya-L1 satellite has been injected into an elliptical orbit of 235/19,500 km, which is a very precise and intended orbit. It is a very unique mission as the two-burn sequence of the upper stage - PS4 - was performed for the first time. For now on, Aditya-L1, after some Earth-bound manoeuvers, will begin its 125 days-long journey to reach the L1 point.” Continued on p5

Aditya an asset to scientific fraternity

Project director Nigar Shaji said once Aditya-L1 is operational, it will be an asset to the heliophysicists of the country and the global scientific fraternity. In the coming days, Aditya-L1 will travel several times around the Earth before being launched towards the L1 point by using onboard propulsion Liquid Apogee Motor (LAM). After exiting Earth’s gravitational Sphere of Influence (SOI), the cruise phase will start and subsequently, the spacecraft will be injected into a large halo orbit around L1, which is located at a distance of 1.5 million km from the Earth - 1 per cent of the Earth-Sun distance.

Former ISRO scientist Mylswamy Annadurai told this newspaper that Aditya L1 will be a technically challenging, scientifically rewarding and operationally meaningful mission. “It will be technically challenging to acquire an orbit around L1 Lagrange point, scientifically rewarding to understand solar activities and model them, and operationally meaningful mission to forewarn disturbance in space weather due to solar activities to take safety measures on the operational satellites.”

The spacecraft carries seven scientific payloads. It will study the solar corona (the outermost layer); the photosphere (the Sun’s surface or the part we see from the Earth) and the chromosphere (the thin layer of plasma that lies between the photosphere and the corona). The studies will help scientists understand solar activity, such as solar wind and solar flares, and their effect on Earth and near-space weather in real-time. Prof Annapurni S, Director of the Indian Institute of Astrophysics (IIA), which provided the primary payload - Visible Emission Line Coronagraph (VELC), said this instrument will look at the corona from the disk of the Sun 24/7. “This instrument was very challenging to make.”

Dipankar Banerjee, Director, of Aryabhatta Research Institute of Observational Sciences (AIRES), said India has a tradition of observing the Sun from the ground. The Kodaikanal observatory is 100 years old. “We have certain limitations as only the lower atmosphere of the Sun will be visible. This Aditya mission is a Lagrange class observatory in space. Internationally, only three such spacecraft belonging to NASA and ESA are hovering near L1.” 

CM KCR PRAISES ISRO FOR ADITYA L1 LAUNCH

Telangana CM K Chandrasekhar Rao expressed his happiness over the successful launch of Aditya L1 by the Indian Space Research Organization (ISRO) on Saturday. 

ROVER IN SLEEP MODE

Chandrayaan 3’s rover Pragyan has completed its work and has been set into sleep mode. “The Rover completed its assignments. It is now safely parked and set into Sleep mode. APXS and LIBS payloads are turned off,” the ISRO said

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