Aditya-L1 begins its long solar voyage

On Sunday, Isro will perform the first Earth-bound firing to raise the orbit of the Aditya-Ll craft

- Soumya Pillai

NEW DELHI: India's first solar mission took off on Saturday, embarking on a 125-day journey before it is placed in a halo orbit around Lagrange Point 1 (L1), a spot between the Sun and the Earth about 1.5 million kilometres from us.

Insertion in Ll will enable the solar observatory Aditya-L1 to monitor the Sun with a "constant, uninterrupted view". But the process for its final placement is long, and requires a series of intricate manoeuvres, the first of which will be performed on Sunday, as the craft uses Earth's gravity to gather momentum.

At 11.45am on Sunday, the Indian Space Research Organisation (Isro) will perform the first Earth-bound firing to raise the orbit of the Aditya-L1 craft and ensure that the craft gains the necessary velocity for its journey. "Aditya-L1 will stay Earth-bound for 16 days, during which it will undergo five manoeuvres to gain the necessary velocity for its journey," a senior Isro scientist explained.

The Earth-bound manoeuvres will involve the rockets firing and some adjustments to angles, as required. How this will work can perhaps be understood by taking the example of when a person is on a swingto make the swing go higher, a pressure (by shifting body weight) is applied when in the phase when the swing is coming down towards the ground. In Aditya-Ll's case, once it gains enough velocity, it will slingshot around to its intended path towards Ll.

"This will mark the beginning of its 110-day trajectory to the destination around the Ll Lagrange point," the scientist said.