The launch vehicle about to blast off from Sriharikota. (AFP)

Sriharikota, Oct. 22: Not once during the 18-minute flight of the rocket ferrying Chandrayaan-1 into space did Isro chairman G. Madhavan Nair turn his gaze away from the computer screen or a sheet of paper on his desk.

As the four-stage Polar Satellite Launch Vehicle (PSLV) climbed into the sky, Nair, flanked by Isro directors M. Chandra Dathan and K. Radhakrishnan, sat stone-faced, watching the rocket perform through a desktop screen.

High above the thick grey-white cloud cover, the PSLV was behaving exactly as it was programmed. A track line on computer screens in the control room here indicated no deviation from its intended trajectory or performance.

As each stage separated and the next one ignited, some engineers in the control room clapped. But Nair allowed himself his first clap 17 minutes after lift-off, only after the fourth and final stage of the PSLV separated.

And about a minute later, after Chandrayaan-1 had successfully separated, he smiled and hugged Radhakrishnan, the director of the Vikram Sarabhai Space Centre, Thiruvananthapuram.

“We had some dramatic moments. It was an ordeal,” Nair said after the launch. “We fought against all odds, and we lost 10 hours in the countdown yesterday,” he said.

Rain, thunder and lightning the previous day appeared ominous. But, Nair said, Isro’s in-house weather scientists had predicted the weather would be good enough for the scheduled launch at 06:22 hours today.

Minutes after the launch, Sriharikota was once again drenched in tropical rain.

But the weather wasn’t the only threat to the launch. A leak while the rocket was being filled with propellant fuel yesterday forced engineers to speed up completion of countdown, Dathan, the director of the Sriharikota centre, told The Telegraph.

The leak was detected in the filling line carrying liquid rocket propellant from the ground to the second stage of the rocket, Dathan said. “Leaks in fuel lines have been observed before, but not this close to the launch time.”

The time spent in tackling the leak took away time from the countdown checks.

Chandrayaan-1 is expected to become the first Indian spacecraft to venture into a realm of space where the gravitational tugs of the sun, the moon and some planets become a lot more significant than Earth’s gravity. “This is an environment we (Isro) have not experienced so far,” Nair said.

The challenge of packing 11 scientific payloads aboard Chandrayaan-1 had added to the complexity of the craft which is carrying five Indian-made instruments, three from the European Space Agency, two from Nasa and one from Bulgaria.

“Calibrating the instruments and ensuring they were all communicating well with systems aboard the spacecraft that will transmit data to Earth — all of this took a little more time than we had expected,” Nair said.