The Indian Space Research Organisation (ISRO) will now go back to the drawing board to plug imperfections in its indigenous cryogenic upper-stage Geosynchronous Satellite Launch Vehicle (GSLV) programme, after the GSLV-D5 mission to launch into orbit the advanced communication satellite GSAT-14, was aborted due to a fuel leak on Monday.

The mission was called off at a fairly advanced stage of the 29-hour countdown, and with only a little over an hour left for the lift-off that was scheduled for 4.50 p.m., at the second launch pad of the Sriharikota spaceport near here.

This was the eighth flight of the GSLV, the fourth developmental flight and only the second time in three years that the indigenously-developed cryogenic upper stage was flight-tested. The Rs. 205-crore expendable rocket’s mission was to inject the cuboid-shaped and 1982-kg weighing GSAT-14 in orbit to signal India’s entry into an ivy league of nations with frontier capabilities of launching 2,000-2,500 kg class of advanced communication satellites in outer space.

The GSAT-14, the 23rd geostationary communication satellite built by ISRO, would have joined a line-up of nine Indian satellites to help provide a host of satellite-based communication services, including tele-education and tele-medicine. The satellite’s mission was also to augment the in-orbit capacity of the extended C and Ku-band transponders in the INSAT-GSAT ecosystem to set the stage for new and exciting experiments driven by satellite-based communication.

The first murmurs of a technical snag that could potentially threaten the mission began to make the rounds at the crowded Media Centre at around 3.45 p.m. Soon came the official announcement from the command centre of the Satish Dhawan Space Centre that the “GSLV launch today is not on” and that a fresh date would be finalised later.

The leak was reportedly observed in the second stage of the 49-metre tall GSLV-D5. The rocket adopts a three-stage fuel cycle — the core solid stage, liquid and a cryogenic upper stage. At about 4 p.m., ISRO Chairman K. Radhakrishnan, accompanied by a team of glum-looking scientists, met the media to formally declare that the GSLV-D5 mission had been called off.

“The countdown was progressing well. However, a few minutes ago, we observed a leak in the fuel systems of the second stage. Because of this, we are calling off the launch,” Dr. Radhakrishnan said.

The immediate task for ISRO teams in the fuel leak situation was to quickly drain out the liquid propellants that had been loaded into the second stage, the four L40 strap-ons and the cryogenic stage, the ISRO chief said.

“We need to make an assessment of the cause of the leak and the actions that need to be taken before further preparations for the next launch,” Dr. Radhakrishnan said. The GSLV-D5 is also being hauled back to the Vehicle Assembly building, he said.

The stakes this time were pretty much sky-high on the ISRO’s cryogenic upper stage rocket, especially after the previous two GSLV missions — in April 2010 and the next in December the same year (with a Russian engine) — had ended in failure. The ISRO had been on a learning curve since, even revisiting the configuration of the GSLV-D5 end-to-end. Not only was the ignition sequence modified and the lower shroud redesigned to provide better insulation for the cryogenic engine, the wire tunnels and the fuel booster turbo pump, too, were retooled.