Joining of two segments to form the 20.1 m long first stage core motor comprising of five segments of 2.8 m diameter. This huge first stage itself accounts for 40% of the height of the 49.13 m tall GSLV D5. Photo Courtesy: ISRO

Five segments are stacked one over the other to form the first stage solid propellant motor of GSLV D5. This motor smokes about 139 tonnes of Hydoxyl-terminated polybutadiene (HTPB) based propellant to produce a maximum thrust of about 4800 kN in about 100 seconds. Photo Courtesy: ISRO

Integration of the 49 m tall Geosynchronous satellite launch vehicle (GSLV D5) began with the stacking of the Nozzle end segment of its mammoth first stage onto the mobile launch pedestal. Photo Courtesy: ISRO

ISRO developed Cryogenic Upper Stage being stacked on the second stage of GSLV-D5 launcher. Photo Courtesy: ISRO

Rocket on the launchpad

Rocket on the launchpad

Launch

Mission details:

• After three difficult years, dogged by the bad luck of two back-to-back failures, and after coming tantalizingly close to a return to flight last summer, the Indian Space Research Organisation (ISRO) is primed to fly its Geostationary Satellite Launch Vehicle (GSLV) Mark II on Sunday, 5 January, 2014. Liftoff has been postponed repeatedly since October 2012, due to ongoing tests of a home-grown Indigenous Cryogenic Upper Stage, which will be making its second flight, and the need to resolve issues which caused the loss of the previous Mark II mission in April 2010. Finally, last August the vehicle underwent a relatively smooth countdown at the Satish Dhawan Space Centre, on the barrier island of Sriharikota, within India’s southern state of Andhra Pradesh. However, a leak was detected in the UH25 (unsymmetrical dimethyl hydrazine) fuel system of the rocket’s liquid-propelled second stage during the pressurization process, and the launch attempt was scrubbed.
• The 29-hour countdown commenced Sunday, 18 August, and encompassed the final loading of liquid propellants—unsymmetrical dimethyl hydrazine and nitrogen tetroxide—aboard the GSLV’s four strap-on boosters and into its cryogenic second and third stages. Both procedures were described by ISRO as “normal,” and it appeared that the detection of the UH25 leak occurred less than two hours ahead of the scheduled liftoff on Monday, 19 August, after which post-scrub efforts to drain the liquid propellants swung into action. Although it was initially reported that the launch window for the GSLV’s “Demonstration-5? (or “D-5?) flight would be kept open for its remaining period from 20 August until 5 September, it soon became clear that the problem would take far longer to resolve.
• In the days that followed, ISRO announced that about 1,650 pounds (750 kg) of unsymmetrical dimethyl hydrazine leaked from the second stage, leading to contamination of the area around the launch pad. “It took six days of round-the-clock operations before the contamination could be reduced to a safe level to enable movement of the GSLV-D5 back to the vehicle assembly building,” ISRO explained, and this rollback was not concluded until 26 August, after which the 161-foot-tall (49-meter) vehicle was destacked. A high level task team, chaired by Shri K. Narayana, the former director of the Satish Dhawan Space Centre, was convened, with suspicion centering on “the lower portion of the propellant tank or the fluid lines between the tank and fuel filling system of the second stage.” A new second stage was assembled and all four strap-on boosters were replaced, with the first stage and Cryogenic Upper Stage inspected for discrepancies and preserved.
• Should the mission fly without incident on Sunday (5 jan 2014), it will mark the second flight of the uprated Mark II configuration of the GSLV and will deliver India’s GSAT-14 communications satellite into orbit. Unlike the earlier Mark I, the Mark II does not rely upon a Russian-built third stage, which ISRO has blamed for failing to operate properly on several occasions, triggering multiple mission failures. The new variant is reportedly capable of delivering a payload weighing up to 11,000 pounds (5,000 kg) into low-Earth orbit and up to about 5,000 pounds (2,270 kg) into geostationary transfer orbit, but both types of the GSLV have exhibited a dismal success record. Launched seven times between April 2001 and December 2010, it has suffered four outright Losses of Vehicle and Payload, one mission in which its satellite cargo was inserted into an improper orbit, and only two full successes.