BENGALURU: The second and final de-orbiting manoeuvre of lander Vikram was held on Wednesday morning. The on-board propulsion system fired for nine seconds, putting the lander in a 35 km x 101 km orbit, the closest it will get to the moon before making its powered descent to the moon’s south pole in the wee hours of September 7. With this, Chandrayaan-2 will create a record, making India the first country to land near the lunar south pole.
From now and until touchdown, ISRO Chairman K Sivan had said, that “scientists will check parameters of the lander to ensure the system is perfect”. The height, velocity, exact position of the lander and condition of about half a dozen sensors onboard will be checked over the next three days, said a senior scientist from the organisation.
All these are crucial for the lander to be settling on the fixed location on the high plains between the two craters - Manzinus C and Simplicius N - at the precise time near the lunar south pole. Even a second’s delay would be akin to landing in Majestic instead of Vidhana Soudha, the scientists explained, while giving an example of how precise the actions will have to be.
While the orbiter continues to orbit the moon in an orbit of 96 km x 125 km, the lander is at the closest point possible to the moon, before it starts towards the moon at a speed of 1.6 km per second till it reaches a point, beyond which, it will move even slower — at two metres per second, said the scientist.
All of this will be part of the 15-minute procedure before touchdown, which the ISRO chief has described as “most terrifying”.
ISRO scientists said that as the lander approaches the moon’s surface, it will begin imaging the landing site to find a safe and hazard-free zone to land. This will be crucial, as an uneven landing site could tilt the lander and make the rolling out of the rover difficult, which in turn, could jeopardise the mission.
The lunar dust settling on the lander is another hurdle for the mission’s success. After a successful landing, the rover will roll out to carry out experiments on the lunar surface for a period of one lunar day, equal to 14 Earth days, while the orbiter will continue its mission for a duration of one year.
The lander will remain static at the landing location, and will relay data of the rover and its own to the orbiter, which in turn, will relay it to the Indian Deep Space Network (IDSN) located at Bylalu, near Bengaluru.
70 students to watch landing live
About 70 students from across the country have been selected to watch the soft landing of Chandrayaan-2 Vikram lander on lunar surface from ISRO’s Bengaluru centre, along with PM Modi.
Students were chosen via a quiz that was held from August 10 to August 25. Top two scorers from each state and UT (between classes 8 and 10) were picked. Ministry of Electronics and Information Technology and ISRO had collaborated for this.