At under $150 million, Chandrayaan 2 is already world's envy, India's pride: K Sivan

Highlights On D-day, anxiety gripped ISRO teams as they approached 20-hour countdown

PM Modi was keeping a close watch on the progress

The soft landing is scheduled in the early hours on September 7

In a remarkable bounce back a week after the Chandrayaan 2 moon mission was aborted, the Indian Space Research Organisation launched the rocket and put the Chandrayaan 2 satellite in a "better than expected orbit" on the afternoon of July 22.

Calling the lift off "an exciting moment", space agency ISRO's Chairman K Sivan in an interview to NDTV said they were "sure that it would be a success".

The night of July 15 when the launch was aborted 56 minutes before lift-off was a nightmare for the ISRO, says Mr Sivan. "It was a hard and infamous (sic) decision but a one-hundred per cent correct decision" as the launch condition was not "conducive", he says, adding a "pressure drop" was noticed in the rocket system due to a "leak".

On that night, President Ram Nath Kovind had already arrived at Sriharikota to see the launch; Mr Sivan says that was also weighing on his mind when the launch was aborted by his team. "There was no pressure from the President's office to have a lift-off," says the ISRO Chairman, adding President Kovind actually "praised us and said continue with the technical activities".

Yet, it was a tough call between a balance of emotions and technical steps, says Mr Sivan, pointing out that it was a correct decision to call off the launch.

The next 24 hours were crucial for the ISRO as at 2 am scientists and engineers at the Liquid Propulsion Systems Centre at Mahendra Giri and the Vikram Sarabhai Space Centre were woken up.

Within an hour, they rushed to Sriharikota carrying advanced equipment and tools. "None of the scientists slept till they had identified the problem," says Mr Sivan.

Even before President had left Sriharikota after breakfast on July 15, the teams of scientists had zeroed in on the possible problem.

Chandrayaan 2: ISRO Chairman K Sivan says the moon mission was a remarkable bounce back

Mr Sivan says they started the complex task of reaching the fully armed rocket since the problem occurred during countdown. There was a complex safety procedure to access the rocket.

Mr Sivan says by T minus 56 minutes, the second stage of the rocket was fully fuelled and the cryogenic engine was half filled. The 640-tonne Geosynchronous Satellite Launch Vehicle Mark 3 (GSLV Mark 3) or the 'Baahubali' rocket was de-fuelled.

Incidentally, taking the rocket to the launch pad takes over 50 days and then there is an intense 20-hour countdown. The fully-armed 44-metre-tall rocket, when ready for lift-off, is a highly potent and dangerous object.

Just to give some perspective, no humans are allowed in a five kilometre radius of the rocket and all operations are done remotely once the countdown starts. The President, the ISRO teams and the media are all located several kilometres away from the rocket for safety.

After the rocket was declared safe to approach, the support structures were brought close to it and the teams of specialists climbed up to the vehicle, says Mr Sivan. "It was a simple to fix problem that got sorted by simply tightening a component," explains Mr Sivan without going into the fine details of the problem.

He says the problem was what can be described as an "unknown-unknown" in rocketry parlance. The same rocket had two consecutive successful launches, but this problem gave them a "scare" since Rs 1,000 crore and national pride were riding on it.

The teams had to make sure by correcting the problem they had not tampered with other systems, so a thorough re-check of the rocket system was done.

Within 48 hours, the problem was resolved and the rocket was handed back to the launch management team, says Mr Sivan. The biggest relief came to them when in the next two days a full rehearsal was successfully completed, after which all systems were "go" and a new launch date of July 22 at 2.43 pm was announced.

On D-day, anxiety gripped the ISRO teams as they approached the 20-hour countdown once again. There was cheering among the onlookers when at T minus 56 minute mark the problem encountered earlier passed off peacefully. The countdown went on unabated and the massive rocket lifted of exactly at 2.43 pm and within 30 seconds disappeared into the clouds and almost 16 minutes later, Mr Sivan announced "bounce back by team ISRO".

Prime Minister Narendra Modi, who was keeping a close watch on the progress of the Chandrayaan 2 mission, sent his key aide in the Prime Minister's Office, PK Misra, Additional Principal Secretary to the PM, to be personally present on the launch pad. PM Modi also sent K Vijay Raghavan, Principal Scientific Advisor to the government, to monitor the second attempt of launching India's 3.8-tonne moon shot.

PM Modi tweeted a photograph of him viewing the launch of Chandrayaan 2

PM Modi himself monitored the launch from his office and was seen clapping when Mr Sivan declared the launch as a success. He told the PM, "We have done it."

PM Modi later told the scientists at ISRO that the bounce back was a "matter of national pride". He expressed happiness that despite the delay of a week, Chandrayaan 2 will still reach the moon on the same date.

The soft landing is scheduled in the early hours on September 7. This was only the first step in the long and arduous journey of Chandrayaan 2 on its 3.84 lakh kilometre, 48-day journey to the moon.

Mr Sivan says, "There will be fifteen terrifying minutes when the Vikram lander finally goes in for soft landing near the south pole of the moon".

Other nations are already eyeing Chandrayaan 2. The American space agency NASA congratulated ISRO, saying it "looks forward to what you learn about the lunar south pole where we will send astronauts on our Artemis mission in a few years".

At under $150 million, Chandrayaan 2 is already world's envy, India's pride, Mr Sivan says with the "lessons learnt", Team ISRO is ready for more challenging missions.

But for Mr Sivan, known as the rocket man of India, and a son of a farmer who studied in a Tamil medium school, the biggest joy will be when India's flag reaches the lunar surface and the Ashoka Chakra is embossed forever on the lunar dust.