A landmark launch

Print edition : June 05, 1999

The launch of PSLV-C2 is a major technological feat of the Indian Space Research Organisation; it also marks the arrival of India in the competitive satellite market.

WHEN the Polar Satellite Launch Vehicle (PSLV-C2) roared into life at the Sriharikota (SHAR) launch pad at 11.52 a.m. on May 26 and injected some 19 minutes later the 1,050-kg Indian Remote-sensing Satellite (IRS-P4) and two foreign-owned satellites into polar sunsynchronous orbits, it accomplished "a very critical operation" of launching three payloads from a single vehicle.

With the deployment of the 105-kg KITSAT of South Korea and the 45-kg TUBSAT of the German Space Agency (DLR), the Indian Space Research Organisation (ISRO) also powered its way into the competitive launch market. These satellites rode piggyback on the m ain mission of IRS-P4. IRS-P4, or Oceansat-I, will map the oceans while KITSAT and TUBSAT are for earth observation (see separate story).

There were scenes of ecstasy at the Mission Control Centre (MCC) as the computer screens flashed the precision sequence deployment of the payloads. Prime Minister A.B. Vajpayee, who flew down to SHAR and watched the launch on closed-circuit television, was "thrilled to watch the mighty engines of the rocket roar and go into space." He said that "it renewed my confidence in the strength and capabilities of our people." Dr. K. Kasturirangan, ISRO Chairman, said that it was "a flawless flight and one of t he best I have ever witnessed." Vajpayee hugged Kasturirangan and warmly shook hands with senior ISRO engineers and scientists, including SHAR Director Dr. S. Vasantha.

Vajpayee said that the launch of three satellites in a single flight was a technological achievement and that it marked India's arrival in the commercial launch market. He said: "ISRO's successful programmes are an illustration of our determination to ma ke India a space power in the next century...In future, many more foreign-owned satellites will be launched on Indian rockets. This shows that our space scientists and technologists are now planting India's flag not just in space but in the global market place."

Former ISRO Chairmen Prof. Satish Dhawan and Prof. U.R. Rao were present on the occasion.

THE four-stage PSLV-C2, weighing 294 tonnes and 44 metres tall, erupted into life with the ignition of the firststage motor and four strap-on boosters. Within seconds the vehicle knifed skywards, riding on a huge tower of orange flame and smoke. A thundr ous roar from its engines jolted across the spindle-shaped Sriharikota island and soon the vehicle disappeared into the clouds.

The MCC was filled with anxiety for the next 19 minutes as it awaited the flight results. Mission Director S. Ramakrishnan kept peering at the computer console. But everything went off according to the pre-determined sequence: the first set of four strap -on motors separated at 68 seconds after lift-off; the second set of two strap-on motors separated at 90 seconds; the first stage jettisoned at 112 seconds; and the second stage ignited immediately thereafter. The heat shield, which protects the IRS-P4 f rom the intense heat and friction generated during the vehicle's ascent into space, split into two when explosive bolts tore it apart. The heat shield fell into the Bay of Bengal at 156 seconds. By now, the vehicle had climbed 125 km into the atmosphere.

The separation of the second stage and ignition of the third stage occurred simultaneously at 281 seconds and the third stage jettisoned at 503 seconds. The last (fourth) stage came to life after a long coasting of the vehicle on its own at 585 seconds a t an altitude of 615 km. The fourth stage burnt out at 984 seconds when the vehicle climbed to a height of 719 km. Finally, the fourth stage pushed IRS-P4 into orbit at 1,010 seconds.

According to Dr. S. Srinivasan, Director, Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, 60 seconds after IRS-P4 was injected into orbit, the fourth stage was reoriented and rotated at 40 degrees, and KITSAT flew out of the equipment bay like a sparrow from its nest. After another 60 seconds the fourth stage was rotated again at 40 degrees, and this time TUBSAT winged out. While these two satellites were located diametrically opposite each other in the equipment bay, IRS-P4 was mounted on top of it, he said. "The sequence of operations was planned in such a manner that there was no collision between the satellites and the fourth stage, which had become a space debris," Srinivasan said.

The Polar Satellite Launch Vehicle (PSLV-C2) rising majestically into the space after lift-off at 11.52 a.m. on May 26 from Sriharikota. The vehicle deployed three satellites one after the other in a pre-determined sequence.-S. THANTHONI

ADDRESSING a post-flight press conference along with the Prime Minister, Kasturirangan said: "It was exactly how a flight should be. We had an excess velocity of 30 metres per second in the penultimate phase. So the control systems corrected it suitably and put it in the right orbit. This is precisely why we have the closed loop guidance system."

G. Madhavan Nair, Director of the Liquid Propulsion Systems Centre at Valiamala near Thiruvananthapuram, whom Kasturirangan described as the "father of the PSLV", told Frontline: "It was one of the most beautiful flights I have seen. It was so pre cise that I can never describe it. It is a fantastic achievement. I think the vehicle is a rugged one... Every mission is a unique mission. This time the stakes were much higher for the simple reason that we had to qualify the system for multiple launche s. Whatever design changes we made based on our previous experience have been validated."

P.S. Goel, Director, ISRO Satellite Centre, Bangalore, where IRS-P4 was integrated, said: "A great launch and a great mission. Our satellite has performed very well. In the next ten days, we will stabilise the operations."

Satellite Director R.N. Tyagi said that the satellite had gone into a near-perfect orbit (of 727 km). Its first payload, the Multi-frequency Scanning Microwave Radiometer (MSMR), was switched on on May 27 and the second payload, the Ocean Colour Monitor (OCM), would be activated eight days after the launch.

Goel said that TUBSAT was switched on eight hours after it was injected into orbit and KITSAT two and a half hours after it went into orbit. The Germans and the South Koreans have their own ground stations to track the satellites and receive data.

MEDIAPERSONS were taken to SHAR four days before the launch. Dr. Vasantha described the PSLV-C2, which stood on the launch pedestal, as "magnificent and awesome". The gargantuan Mobile Service Tower (MST), inside which the PSLV was assembled, was moved b ack on its wheels on rail tracks. The vehicle was painted in white and red. The national emblem was painted on top of the rocket and the tricolour below it, flanked by German and South Korean flags. Below them were the logos of TUBSAT, Oceansat and KITSA T in that order.

According to Vehicle Director K. Ramachandran, launching three satellites from a single vehicle constituted "a major change" and a big challenge. Modifications were made in the equipment bay to accommodate the two small foreign spacecraft. "This is one o f the most cost-effective launchers of this class. The vehicle's performance was excellent in all pre-launch tests. With this successful flight, we expect a flurry of offers," he said.

M.K. Abdul Majid, Deputy Director of Mechanisms, Vehicle Integration and Testing at the VSSC, said that the modifications made in the equipment bay would be a permanent feature. "With streamlined integration of the vehicle, we are ready to enter the oper ational phase," he said.

P.S. Veeraraghavan, Director, Launch Vehicle Integration, said that with the experience gained from integrating the previous four PSLVs, the launch campaign time had been reduced from 120 days to 60 days. "The launch campaign went off smoothly. We are en tering the operational and commercial phase," Veeraraghavan added.

Dr. A.K.S. Gopalan, Director, Space Applications Centre, Ahmedabad, described IRS-P4 as "the ocean mission" of ISRO, which hitherto concentrated on mapping the earth's resources. The OCM will take pictures of the chlorophyll concentration. Gopalan said: "Wherever there is a high content of chlorophyll (in the sea) and .... a combination of temperature, you can expect fish there. So we can locate potential fishing zones more accurately. This will be helpful to fishermen. This is a major application."

At the post-launch press conference, ISRO Chairman Dr. K. Kasturirangan presents a model of the Indian Remote-sensing Satellite to Prime Minister A.B. Vajpayee.-S. THANTHONI

The MSRM will monitor the entire globe in two days and provide information on sea surface winds, wave structures, water vapour in the atmosphere and so forth. Gopalan said that these parameters would be given to meteorologists who would study and model t hem for weather forecasts.

KITSAT is an engineering satellite whose main objective is to develop fundamental technology for high performance micro-satellites. TUBSAT will carry out tests on advanced technologies involving three-axis attitude control.

Sungheon Kim of the Satellite Technology Research Centre of Republic of South Korea, said that "ISRO was ready to give us the space and it was a good opportunity for us (to fly KITSAT)." Stefan Shulz of the Technical University of Berlin, said that TUBSA T would be used for earth observation.

ACCORDING to Ramakrishnan, ISRO engineers started tacking the four stages of the launch vehicle in the MST from March 2. IRS-P4 was mated with the vehicle on May 16, and the two passenger payloads were subsequently integrated in the equipment bay.

He said: "We were able to cut down the total vehicle assembly time from 100 days during the first launch to 55 days now." The countdown time for the two developmental launches, which stood at 72 hours, was reduced to 52 hours.

Kasturirangan said that the project costs for PSLV-C2 and IRS-P4 were Rs.70 crores and Rs.48 crores respectively. On the fee charged to launch KITSAT and TUBSAT, he said that the usual cost of launching a 100-kg passenger payload was about $1 million. "T his is our first venture. One of our customers has been a traditional partner in our space programme. For the two customers, we have a promotional price," he said. ISRO's prices were competitive - 20 to 30 per cent lower than those of others because the expenditure on the fabrication and testing of vehicles is relatively low, he said.

S. Shankar, Chief Range Safety Officer who keeps tabs on the trajectory of the vehicle, said that this was the first time that foreign countries had used an ISRO vehicle to fly their satellites. Although ISRO had flown DLR payloads before, they were part of the main payload built by ISRO, he pointed out.

Antrix Corporation, the commercial wing of ISRO, is marketing PSLV to launch foreign satellites. Kasturirangan said: "We have a booking for one of the future missions for a satellite from Belgium, called Proba. It is a 100-kg satellite. We plan to fly it in one of the next PSLV missions around 2000." He explained that the idea of launching small satellites which rode piggyback on the primary satellite was not to recover the cost but to enable the conduct of experiments. He said that PSLV-class vehicles could be made available for such missions to launch IRS-class satellites weighing about 1,000 kg into polar orbits, and to put satellites weighing between three and four tonnes into low-earth orbits. Depending on the need of the customer, ISRO could offe r this variety, he said.

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