No technology, however complex and challenging it might be, is beyond India’s capability to develop and deploy from ground zero. And this truism was amply demonstrated by the spectacularly successful flight of the heaviest ever Indian rocket, the three stage 414.75-tonne Geosynchronous Satellite Launch Vehicle (GSLV), the “crowning glory” which was the home grown, upper cryogenic engine stage. The January 5 flawless mission of GSLV, which placed into orbit the 1982 kg GSAT-14 communications satellite, has verily boosted India’s prestige sky high in one quick sweep. The 17-minutes long “text book” perfect mission of GSLV encasing the painstaking endeavours of ISRO (Indian Space Research Organisation) spread over twenty years catapulted India into the ranks of elite space faring countries—USA, Russia ,China, Japan and European Space Agency(ESA)—which have the proven capability to build and launch cryogenic fuel driven space vehicles.
The precise performance of the Indian cryogenic engine which-- burnt for a total 12 minutes-- was such that the GSAT-14 spacecraft was injected into the orbit with a perigee (lowest point) of 176-km against the calculated value of 180-km and the apogee (farthest point) achieved was off the mark by a mere 50-kms from a target of 36,000-km.
ISRO Chairman K Radhakrishnan was right in his observation, “With the successful GSLV programme, we have paid back all the debts to the country.” The vibrant technological breakthrough achieved by the successful GSLV flight has brought to the country a range of long term, immense and diverse benefits spanning strategic, commercial industrial and space exploration sectors.
But then the most telling and conspicuous message of the unqualified success of GSLV is that India don’t need to care or worry about the notorious technology denial regime spearheaded by USA. The successful development and flawless performance of the cryogenic engine stage built by ISRO, virtually from scratch, stands out as a challenge to USA which left no stone unturned to prevent India from accessing the critical cryogenic engine technology which continues to be a zealously guarded secret. On a more practical plane, the success of GSLV has helped ISRO cross a higher technological threshold in its quest to sustain India’s leadership position in space. As picturesquely pointed out by K.Sivan, GSLV Project Director, the indigenous cryogenic engine has given wings to GSLV which had suffered “setbacks and failures” that had come in for flak from the media.
More importantly, the successful flight of GSLV has helped ISRO break the technological barrier for building better, bigger and more powerful launch vehicles designed to meet the growing and varied needs of India in space sector in the years ahead. For with a single operational vehicle in the form of the four stage PSLV(Polar Satellite Launch Vehicle) with a modest launch capability, ISRO had to look beyond the shores of the country for getting its heavier class INSAT/GSAT satellites off the ground at the head of procured launchers whose launch fee involved a huge outgo of foreign exchange. For instance, ISRO had to pay something like US$85-90 million (around Rs.5000 million) as a launch fee for getting its 3.5-tonne class satellite launched. In contrast, a single flight of GSLV costs just Rs.2200 million. This implies that with GSLV at its disposal, India will be in a position to take care of the orbital missions of home-grown satellites in 2-.2.5-tonne class. What’s more, by offering the services of GSLV for the global customers planning to get their commercial class communications satellites off the ground, India can stand to earn a tidy launch fee. By all means, ISRO is in a very comfortable position to offer a highly competitive fee—in comparison to European and American commercial space launch service—for the services of GSLV. Radhakrishnan has made it clear that with one more fight, GSLV will be ready for commercial use. ”After flying one more GSLV, we will be in a position to declare the rocket as a commercially operational,” noted Radhakrishnan. The next flight of GSLV, which will carry GSAT-6 communications satellite into orbit, is planned to be achieved within a year from now.
Without doubt, a home grown high performance launch vehicle capable of meeting Indian needs for launching heavier class satellites makes for a strategic sense in that it could insulate the country from the uncertainties that the multi billion dollar global space launch market could face in the future due to shifting political and geostrategic priorities. Further, with a heavy lift off space vehicle at its command, there is no need for India to worry about the notorious technology denial regime as exemplified by the US trade sanctions and technology embargo. ISRO has for long remained a favourite target of US trade sanction. But then the trade sanction instead of hitting ISRO has only contributed to the steady decline in the volume of business carried out by US companies specializing in space technology. On the other hand, the trade sanction provided the incentive to develop the technology indigenously and here ISRO has come out with flying colours. Occasional failures and setbacks have not dampened the spirits of ISRO in its endeavour of taking India to new heights of glory.
In the immediate future, ISRO has lined up a series of satellites for launch by means of GSLV. Beyond this, GSLV will also be the vehicle of choice for launching India’s high profile missions like Chandrayaan-II robotic probe to moon and follow on missions to Mangalyaan orbiter spacecraft to Mars launched in November last. However, the high point of GSLV is that it has smoothened the path of qualifying the heavy lift off GSLV-MKIII vehicle which would be used for the proposed Indian human space flight mission projected for the second half of this decade. With the experience of the successful GSLV flight behind it, the qualification process of the three stage 630-tonne GSLV-MKIII has now become a less challenging task. As pointed out by Radhakrishnan, the three stage GSLV-MKIII with an upper cryogenic engine stage will be flight ready in around three years from now. An experimental mission of GSLV-MKIII is planned to be accomplished in April this year. ”The rocket will have a passive cryogenic stage/engine. The main purpose of the mission is to study the aerodynamics and stability of the rocket,” said Radhakrishnan. To support the operations of heavy lift space vehicles like GSLV-MKIII, a third launch pad is being set up at the Satish Dhawan Space Centre (SDSC),the Indian space port on the spindle shaped Sriharikota island on India’s eastern coast. It will be bigger and better than the existing two launch pads. Incidentally, ISRO has a very crowded schedule ahead of it as it has lined up around 50 missions for launch—that would use both PSLV and GSLV-- over the next five years.
The first mission of GSLV carrying an indigenous cryogenic engine in April 2010 had ended up in failure. This failure was traced to the “below par” performance of the fuel booster turbo pump feeding liquid hydrogen to the combustion chamber. Following this, the booster turbo pump was modified and subjected to extensive testing. And once again in August last, the GSLV flight meant to evaluate the performance of the home grown cryogenic engine was called off at the last moment following the detection of leak in liquid fuel driven second stage of the vehicle. In the light of this development, ISRO modified the second stage fuel tank of the vehicle with the use of new high strength aluminium alloy. All in all, ISRO was extremely cautious this time around in tightening the gaps in the design parameters of GSLV.A number of design modifications were implemented followed by a series of ground tests including high altitude tests simulating the actual conditions under which the cryogenic engine stage of the vehicle would perform. Indeed, as a confident Radhakrishnan stated before the GSLV launch, nothing has been left to chance.
Indian industries, in both the private and public sectors, have contributed actively to the development of cryogenic engine stage. ISRO is currently developing cryogenic engine in partnership with a consortium of private industries—Godrej of Mumbai and MTAR Technologies of Hyderabad. Meanwhile, a Rs.1390 million facility is being set up at the Bangalore complex of the state owned Indian aeronautical major HAL (Hindustan Aeronautics Limited) to produce cryogenic engines and complex components of GSLV and the futuristic launch vehicles. This facility is expected to be ready by 2016. Indian industries participating in the development of cryogenic engine have been able to upgrade their skill level and expertise in a number of areas of cutting edge, frontier technologies.
The importance of cryogenic propulsion system lies in the fact that it is capable of delivering a heavier payload into the orbit in comparison to the non cryogenic propellants used in the earlier generation PSLV. For the specific impulse of generated by the cryogenic fuel is much higher than the conventional solid and liquid fuel systems. Specific impulse denotes the volume of thrust generated by a rocket engine per unit of fuel burnt per unit of time. But then the biggest technological challenge involved in developing a cryogenic engine system lies in handling oxygen which remains liquid only at temperatures below minus 183 degree Celsius and hydrogen which remains liquid at below minus 253 degree Celsius. The crux of the problem lies in handling these volatile fuel systems in a very regulated and efficient manner under actual flight conditions. And this is an area where ISRO has excelled. ISRO could handle the development of cryogenic engine, which was a really complicated job involving as it does the mastery of materials technology , operation of turbo pumps and turbines that operate at cryogenic temperature, with a high degree of confidence. Incidentally, the Indian cryogenic engine works on “staged combustion cycle” technique wherein hydrogen is partially burnt with a little oxygen in the gas generator. The hot gases, which drive the fuel booster turbo pump, are injected at high pressure into the thrust chamber where the rest of oxygen is introduced to facilitate the fuel combustion. Before going to the gas generator, the incredibly chilly liquid hydrogen is used to cool the thrust chamber whose temperature rises abnormally high when the engine is fired.
As it is, ISRO was exploring the possibility of developing an indigenous high performance cryogenic engine in 1980s.But at that point of time, India’s maturity in space technology left much to be desired. As such, India started looking for the acquisition of this critical rocket technology from abroad. But since the cost of cryogenic engine technology offered by Americans and Europeans was quite stiff, ISRO decided to go in for the offer made by Soviets. The Soviet Glavkosmos came forward to supply two flight ready cryogenic engine stages along with the technology transfer for a modest fee of US$200 million. And in early 1991, ISRO signed a contract with the Glavkosmos for the acquisition of the technology for accelerating the development of the cryogenic engine stage for GSLV. The first two stages of GSLV are derived from the modules of PSLV.
As per the Indo-Russian agreement, only the propulsion hardware was to be made available by Glavkosmos whereas the control system required for the stage and mission management such as sequencing, tank pressure control, thrust and mixture ratio control, gimbal control and post flight passivation as well as facilities required for stage preparation and propellant servicing were to be developed by ISRO. The Russian cryogenic engine was based on the KVD-1 technology developed for the Soviet era N-1 rocket.
But then geo political developments came in the way of taking Indo-Russian agreement to its logical culmination. USA, which could not relish the prospect of India emerging a major player in the area of space exploration, arm twisted Russia into dropping the plan for transferring the cryogenic engine technology. In fact, the US strategy was smoothened by the unceremonious breakup of the Soviet Union. In the context of the changed geographical reality, USA could easily coerce a politically emaciated and economically bankrupt Russia to fall in line with its dictate. By citing the provisions of the so called Missile Technology Control Regime (MTCR), USA pressurised Russia into going back on its commitment of transferring the cryogenic technology to India.
The US argument that cryogenic engine makes for dual use does not make any sense. For the cryogenic propulsion system is hardly used in a missile system as it is not possible for stuffing the cryogenic fuel into the missile system in advance. Since a missile should be in a fully well ready mode to hit back without any loss of time, normally the earth storable solid fuel is packed into the missile. And ultimately, as a face saving device, the Indo-Russian agreement was diluted down to the supply of seven flight ready cryogenic engine stages to help India sustain the flights of GSLV till such time as a home grown cryogenic engine stage gets ready. Out of the seven Russian engines, six have already been used by ISRO. Out of the six GSLV flights with the Russian upper cryogenic engine stage, three have been a “total flop”. It is a tribute to the technological excellence achieved by ISRO that it could master the highly complex cryogenic propulsion system of Russian origin against heavy odds. With the cryogenic engine technology under its belt, ISRO is now well poised to steer India into the greater heights of space accomplishment. Not even sky seems to be the limit for ISRO.
Published Date: 9th May 2014, Image source: http://dd508hmafkqws.cloudfront.net