After a successful landing on the Moon recently, the Indian Space Research Organisation (ISRO) on Saturday launched its Aditya-L1 mission to study the Sun. Aditya-L1 is the first space-based observatory-class Indian solar mission to study the Sun. In a text book launch, the Aditya-L1 satellite was separated after 63 minutes of the lift off.

ISRO’S Aditya-L1 lifts off aboard the PSLV-C57 rocketVideo Credit: TE Raja Simhan

At 11.50 a.m., the ISRO’s workhorse Polar Satellite Launch Vehicle (PSLV) blasted off from the second launch pad of the Satish Dhawan Space Centre SHAR, Sriharikota. On a hot and sunny day, PSLV-C57 emerged behind the trees - as visible from the terrace of the media centre about 3 km from the launch pad - and soared with a thunderous sound. The rocket with red orange flame in its tail left behind thick smoke as it went towards the sun.

63-minute separation

The regular PSLV places the spacecraft into an orbit roughly under 25 minutes from lift-off. However, Aditya’s separation happened 63 minutes after the rocket blasted off.

ISRO Chairman S Somanath after the successful launch from the control room said, “Aditya L1 spacecraft has been injected in an electrical orbit of 235/19,500 km, which is intended very precisely by the PSLV. This is a unique mission mode with the upper stage of the PSLV making two burn sequences for injecting the primary satellite for the first time. I want to congratulate PSLV for a different mission approach today to do this mission of Aditya L1 to put it in the right orbit. From now, the Aditya L1 will take its journey after some earth manoeuvres and start the journey to the L1 point. It is a very long journey of 125 days,” he said.

Jitendra Singh, Minister of State for Science and Technology, said while the whole world watched this with waited breadth, it is indeed a sunshine moment for India. Indian scientists have been working, toiling day and night for years together but now comes the moment of vindication, the moment of redeeming the pledge to the nation.


The 1,420 kg, 44.4 m PSLV XL carried seven payloads to observe the photosphere, chromosphere, and the outermost layers of the Sun (the corona) using electromagnetic and particle detectors. Using the special vantage point of L1, four payloads will directly view the Sun and the remaining three payloads will carry out in-situ studies of particles and fields at the Lagrange point L1.

The suit of Aditya L1 payloads are expected to provide most crucial information to understand the problems of coronal heating, Coronal Mass Ejection, pre-flare and flare activities, and their characteristics, dynamics of space weather, study of the propagation of particles and fields in the interplanetary medium.

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.

Significance of L1

L1 here refers to Lagrange Point 1 of the Sun-Earth system. For common understanding, L1 is a location in space where the gravitational forces of two celestial bodies, such as the Sun and Earth, are in equilibrium. This allows an object placed there to remain relatively stable with respect to both celestial bodies.

Following the launch, Aditya-L1 will stay in Earth-bound orbits for 16 days, during which it undergoes five manoeuvres to gain the necessary velocity for its journey. Subsequently, Aditya-L1 will undergo a Trans-Lagrangian1 insertion manoeuvre, marking the beginning of its 110-day trajectory to the destination around the L1 Lagrange point. 

Upon arrival at the L1 point, another manoeuvre binds Aditya-L1 to an orbit around L1, a balanced gravitational location between the Earth and the Sun. The satellite spends 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, ISRO said.

Quick facts

Aditya-L1 will stay approximately 1.5 million km away from Earth, directed towards the Sun, which is about 1 per cent of the Earth-Sun distance. 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.