After an agonizing three years of introspection and an enormous amount of work, the Indian Space Research Organisation (ISRO) has successfully launched its trouble-plagued Geostationary Satellite Launch Vehicle (GSLV) to deliver the GSAT-14 communications satellite into orbit. Liftoff occurred on time at 4:18 p.m. India Standard Time (10:48 a.m. GMT) Sunday from the Satish Dhawan Space Centre, on the barrier island of Sriharikota, within India’s southern state of Andhra Pradesh. In addition to helping restore the reputation of a rocket whose dismal record previously stood at just three successes in seven launches, the mission secured its place as the world’s first orbital space launch of 2014.
The GSLV program has been dogged by two back-to-back launch failures, in April and December 2010, and came tantalizingly close to a return to flight last 19 August, when a leak of unsymmetrical dimethyl hydrazine from the second stage was detected and the mission aborted less than two hours before liftoff. Although it was initially reported that the launch window 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 India’s home-grown Indigenous Cryogenic Upper Stage (CUS) inspected for discrepancies and preserved. Finally, the GSLV-D5 was rolled out from its assembly building to the launch pad’s umbilical tower on 28 December, and the 29-hour countdown commenced yesterday (Saturday) at 11:18 a.m. IST.
Half an hour after the start of countdown operations, the process to load unsymmetrical dimethyl hydrazine and nitrogen tetroxide propellants into the rocket’s second stage (GS2) kicked into action. This process concluded at 6 p.m. IST and was followed by the loading of the four liquid-fueled strap-on boosters, which was itself completed early Sunday morning. Finally, at 11:42 a.m. IST Sunday, the process of chilling down the fuel lines and filling the CUS with liquid hydrogen and oxygen got underway, and the vehicle was declared ready for launch about 30 minutes ahead of the scheduled liftoff time.
As intended, the Vikas engines of the four liquid-fueled boosters ignited at T-4.8 seconds, after which the “core” stage—which utilizes a solid propellant of hydroxyl-terminated polybutadiene—roared to life at T-0, and with a combined 610,000 pounds (276,700 kg) of thrust the GSLV-D5 left the pad at 4:18 p.m. IST (10:48 a.m. GMT). “First stage performance nominal” came the call from the launch commentator, a minute into the flight, and the core shut down as expected at 4:20 p.m. IST (10:50 a.m. GMT), followed by the strap-on boosters at T+2 minutes and 29 seconds. To applause in ISRO Mission Control, the GS2 second stage ignited at T+2 minutes and 29.5 seconds, and the first stage separated about 1.5 seconds later. The vehicle continued to climb under the impulse of its own Vikas engine, which burned with 160,000 pounds (72,580 kg) of thrust for about 150 seconds, during which time the payload fairing was jettisoned at 4:22 p.m. IST (10:52 a.m. GMT) to expose the GSAT-14 primary payload.
By this point the rocket had attained an altitude of about 75 miles (120 km), and the GS2 second stage was shut down a minute later and separated at T+4 minutes and 52 seconds. Next came the turn of the troubled CUS, which represents India’s effort to develop a home-grown cryogenic upper stage engine and eliminate its reliable upon foreign vehicles—including Europe’s Arianespace—to deliver its geostationary satellites into orbit. The CUS ignited perfectly at T+4 minutes and 53 seconds and burned without incident, “within the performance limits” and described as “exactly as planned,” for 12 minutes. Its engine produced 16,500 pounds (7,480 kg) of thrust. It shut down successfully at 4:35 p.m. IST (11:05 a.m. GMT), and the GSAT-14 payload separated shortly afterward into a geostationary transfer orbit of 112 x 22,300 miles (180 x 36,000 km), to tumultuous applause at ISRO Mission Control.
Speaking after the launch, ISRO Chairman Mr. K. Radhakrishnan described a “major achievement for the GSLV program” and paid particular tribute to a team which had endured an “excruciating” three years of disappointment and engineering challenges. He recognized 20 years of work by Indian engineers and managers to develop the CUS and highlighted the fact that last August’s last-minute scrub of GSLV-D5 was an indicator of “the maturity of the team.” Mr. Radhakrishnan then summoned other key figures in the GSLV and CUS program to share a few words, and some levity was provided by Mission Director Mr. K. Sivan, who described the success in a handful of words: “The naughty boy becomes obedient!”
Today’s mission has been called a “landmark achievement” for India, producing a “wonderful feeling of success” and a “very proud moment,” but it must be borne in mind that the GSLV has flown well in the past and been declared operational, only to succumb to a subsequent accident. The mission is only the second flight of the GSLV’s uprated Mark II configuration, which, unlike its predecessor, the Mark I, relies upon India’s CUS, as opposed to a Russian-built third stage. ISRO has repeatedly blamed the Russian stage for having failed to operate on several occasions, triggering multiple failures, and the CUS 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.
However, launched seven times between April 2001 and December 2010, the GSLV 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. The three-stage rocket was originally conceived as a means of eliminating India’s reliance upon foreign rockets for its geostationary-orbiting satellites. It utilizes components of the highly reliable Polar Satellite Launch Vehicle (PSLV) and comprises a first stage fed by a single solid-fueled engine and four strap-on liquid-fueled boosters, topped by liquid-fueled second and third stages.
Its maiden (“Development-1,” or “D1”) voyage in April 2001, flying in the Mark I(a) configuration, suffered an engine shortfall when its Russian-built upper stage burned for 12 seconds less than planned. This delivered the GSAT-1 payload into an improper orbit, whose apogee was 2,500 miles (4,000 km) lower than intended. Although ground controllers managed to nudge the satellite toward geostationary orbit, they did so at the expense of using all of its attitude control propellant, and GSAT-1’s tasks of digital audio broadcasting, compressed digital television signal transmission, and associated internet services could not be achieved.
Success was finally achieved two years later, in May 2003, when a second Mark I(a) vehicle flew the “D2” mission and placed GSAT-2 into geostationary orbit. Perhaps a little prematurely, the GSLV was declared operational, and in September 2004 it carried the EDUSAT/GSAT-3 payload into orbit to handle India’s demands for an interactive satellite-based education system. However, success and failure went hand in hand, and in July 2006 the uprated Mark I(b) configuration veered outside permitted limits during ascent and had to be remotely destroyed over the Bay of Bengal by the range safety officer. Its primary payload—the Insat-4C multi-purpose satellite—was lost in the accident.
Another Loss of Vehicle event occurred in September 2007, when a Mark I(b) suffered an underperformance of its third stage and failed to deliver Insat-4CR into geostationary orbit, due to a guidance system error. The satellite was eventually maneuvered into its proper orbit by ground controllers, but at the expense of reducing its operational lifetime from 10 to five years. Two more failures followed. The first flight of the new Mark II vehicle (“D3”) in April 2010, with its ISRO-designed cryogenic third stage, developed a turbopump fault and resulted in the loss of the GSAT-4 communications and navigation satellite. This would have been India’s first spacecraft to utilize ion propulsion. Most recently, on the “D4” mission in December 2010, a Mark I(c) was lost when its four liquid-fueled boosters failed to respond to commands, and the vehicle and GSAT-5P communications satellite payload had to be destroyed by the range safety officer.
Late in 2011, S. Ramakrishnan, head of ISRO’s Liquid Propulsion Systems Centre (LPSC) at Mahendragiri, declared that the GSLV-D3 turbopump fault had been isolated, corrective actions taken, and computer simulations concluded and validated. “We did a thorough analysis of the D3 flight and identified the reasons behind its failure,” explained P.S. Veerarghavan, director of Vikram Sarabhai Space Centre. “The analysis called for a redesign of certain components in the cryogenic propulsion system and the same has now been addressed and is being put through multiple testing.” Key focuses included high-altitude “hot-fire” tests to verify the performance of the third stage turbopump. Other recommended steps included strengthening the payload shroud. In early May 2013, the CUS for the GSLV-D5 mission was transferred from LPSC Mahendragiri to Sriharikota for final checkout. On 5 July, the process of integrating the upper stage with the lower two stages of the GSLV got underway.
Today’s triumphant launch increases ISRO’s confidence in a rocket which is expected to carry the long-awaited Chandrayaan-2 mission in 2015. The latter will place a spacecraft into orbit around the Moon and deploy a landing craft and a single roving vehicle to touch down on the surface. Although this will be India’s second mission to the Moon, it will be markedly more complex than its predecessor, the 2008-launched Chandrayaan-1. For now, the safe arrival of GSAT-14 in orbit will provide a replacement for the EDUSAT/GSAT-3, which has been operational for almost a full decade. The 4,400-pound (2,000-kg) GSAT-14 is equipped with six Ku-band and six C-band transponders, which will cover the entire subcontinent of India, together with Ka-band beacons for studying the impact of climate on the Ka-band satellite communications links in the region. GSAT-14 will remain operational for about 12 years at 74 degrees East longitude.