Nandkumar M Kamat
Finally, India’s second mission to the moon is right on target. The July 15 launch was aborted just an hour before the ignition. ISRO engineers corrected the fault without dismantling the rocket or shedding the fuel. The problem was related to getting proper pressure in liquid fuel tanks. This ensures continuous flow of fuel to the combustion chamber. Helium gas is filled from the top and liquid fuel is pumped in the combustion chamber from the bottom. For a rocket to take off it is very important to get uniform flow of fuel in the combustion chamber.
The expert committee which analysed the launch problem on July 15 found that the failure was caused by a propellent regulator in one of the four strap-on liquid motors which had much higher discharge coefficient in its closed condition.
As I complete 61 years today, it is for me an occasion to celebrate the success of Indian Space Research Organisation -ISRO which we saw growing by leaps and bounds as our post 1960 generation grew up simultaneously and we became witnesses to every historic launch event.
I can’t forget the news of the launch of the first Indian satellite Aryabhatta on April 19, 1975. I had just finished my SSC examinations and there was lot of excitement in the country. Thereafter hardly any years passed without ISRO making us notice its feats. By now ISRO has on record 74 launch missions, 105 spacecraft missions and it has launched 297 foreign satellites. ISRO has 10 satellites weighing more than three tones in orbit. The life of INSAT-4A AND 4B is over. We were also unhappy when there were failures. PSLV failed twice, GSLV failed thrice, but ISRO learnt from its mistakes and technical faults and triumphed in the next attempt. So ISRO became part of our consciousness.
On July 22 after the successful insertion of Chandrayaan-2 in orbit around Earth, ISRO proved that it has the capacity to overcome last minute glitches because the termination of the prescheduled launch on July 15 had created an atmosphere of national gloom, distrust, suspicion, and doubt. Very few people know how ISRO employees worked day and night till the fault was rectified. Many forgot their lunches and dinners and cut off any communication with their families in order to fully focus on the repair work. As the countdown for the ignition of the GSLV-Mark III began on July 22 there was terrific, palpable tension in air. In the final ten seconds people were holding their breath. But ISRO triumphed and within minutes India erupted in celebration.
What is the status of Chandrayaan-2 mission now? First the earth-bound orbit-raising manoeuver for Chandryaan-2 spacecraft was performed successfully on July 24, 2019 as planned, using the onboard propulsion system for a firing duration of 48 seconds. Further major activities include, the remaining earth-bound maneuvers, trans lunar insertion, lunar-bound maneuvers, Vikram Separation, and Vikram Touch Down.
The second earth-bound orbit-raising maneuver for Chandryaan-2 spacecraft was performed successfully on July 26, 2019 at 0108 hrs (IST) as planned, using the onboard propulsion system for a firing duration of 883 seconds. The orbit achieved was 251 x 54829 kilometres. ISRO reported all spacecraft parameters normal. The third orbit raising manoeuver is scheduled on July 29, 2019, to raise it to 268 x 71558 kilometres. The fourth orbit raising maneuver is scheduled on August 2 to raise it to 248 x 90229 kilometres and slowly Chandrayaan -2 will begin to lose gravitational grip of Earth as it enters lunar gravitational influence. On August 6 it will be raised again to acquire a very odd looking 221 x 143585 kilometre orbit and on August 14 if you wish to know its whereabouts then it would be 266 x 413623 kilometres. By August 20, ISRO will insert it into the lunar orbit and an important stage of the whole mission will be achieved.
What next? We need to wait eagerly till September 7. Once again, the nation will hold its breath because the success of the mission will depend on the soft landing of the lander on the moon. According to ISRO- after August 20, on entering moon’s sphere of influence, on-board thrusters will slow down the spacecraft for lunar capture. The orbit of Chandrayaan-2 around the moon will be circularised to 100 x100 kilometres orbit through a series of orbital maneuvers. On the day of landing, the lander will separate from the orbiter and then perform a series of complex manoeuvers comprising rough braking and fine braking. Imaging of the landing site region prior to landing will be done for finding safe and hazard-free zones. The lander-Vikram will finally land near the south pole of the moon on September 7. Subsequently, the rover will roll out and carry out experiments on the lunar surface for a period of one lunar day which is equal to 14 Earth days. The orbiter will continue its mission for a duration of one year.
So for the next two months Chandrayaan-2 will occupy media center-stage thanks to the spirit of ISRO. These two months mean a lot to my generation because we know that the next generation of Indians will have the opportunity to visit India’s colony on moon. That is our real goal and dream. Make the moon India’s next frontier.