A Feather in the Cap of the Indian Space Programme

Abstract:  The successful GSLV-MKII mission of August 27 has been described as a shot in the arm for the Indian Space Research Organisation(ISRO). It will help the Indian space agency to build  bigger and more powerful launch  vehicles by scaling up the cryogenic propulsion technology originally developed to power GSLV-MKII. What’s more, the option of exploiting the commercial potentials of GSLV-MKII and its high performance version, GSLV-MKIII now under development, has all the potentials to turn India into a space power of global standing.

In a major boost to the Indian space programme, the mark  two version of the three-stage, heavy-built Geosynchronous Satellite Launch Vehicle(GSLV-MKII), powered by a fully Indian cryogenic engine upper stage, pulled off a successful orbital mission on 27August. This second successful space debut of GSLV-MKII carrying a home grown cryogenic stage delivered a high-powered GSAT-6 communications satellite weighing 2117kg into its intended orbit  with “text book” precision. It took around seventeen minutes for the 416-tonne heavy GSLV-MKII, after its flawless take off from the second launch pad of the Satish Dhawan Space Centre(SDSC) in Sriharikota island in the Bay of Bengal, to accomplish its mission. This launch has helped Indian Space Research Organisation(ISRO) establish the operational efficiency and reliability of the domestically-built cryogenic engine stage, which symbolises two-decades long painstaking toil of Indian space scientists who fought against heavy odds to  realize this advanced  rocket propulsion system. With a thorough mastery of the nuances of cryogenic propulsion system, which involves the use of propellants in extremely low temperature, ISRO has broken the barriers insofar as scaling up the home grown launch capability is concerned.

There is no denying the point that the technology of cryogenic propulsion is both tricky and challenging.  And India happens to be the sixth nation to have mastered the technology of cryogenic engine which is a closely guarded preserve of advanced space-faring nations. Cryogenic propulsion system involving the use of propellants at extremely low temperature is capable of delivering a heavier payload into the orbit compared to non-cryogenic rocket fuels, as the specific impulse generated by the cryogenic fuel is much higher than the conventional solid and liquid fuel systems. The biggest technological challenge involved in developing a cryogenic engine system lies in handling oxygen which remains liquid only at a temperature below minus 183 degree Celsius and hydrogen which remains liquid at below minus 253 degree Celsius.

The commendable achievement of the Indian space agency in terms of overcoming the technical obstacles in realizing a cryogenic propulsion system opens up an exciting possibility of building a range of rocket variants with widely varying lift-off capability. So far, India had to make do with the limited capability of the solitary operational vehicle in the form of the four-stage Polar Satellite Launch Vehicle(PSLV) described as the reliable Indian space workhorse. Taking the legacy of GSLV-MKII (the first two stages of which are derived from PSLV)forward, ISRO is already into developing a heavy lift GSLV-MKIII. Everything going as planned, the 630 tonne GSLV-MKIII capable of carrying a 4-tonne class satellite payload into a geostationary transfer orbit will have its full-fledged debut flight by the end of 2016.As it is, the suborbital experimental flight of GSLV-MKIII carried out in Dec.2014, had lofted a prototype of manned capsule to evaluate its performance during the critical re-entry stage. Also, GSLV-MKIII is planned to be used for India’sproposed manned space flight programme which is yet to get the green signal from the Indian government.

The GSLV MKII, designed to launch a satellite weighing upto 2.5 tonne, will help India end its dependence on procured commercial launch service for orbiting INSAT/GSAT satellites with a take-off weight below 2.5-tonne.Falling back on the commercial launch service for getting the satellites off the ground makes for a massive outgo of foreign exchange. The “launch independence” assured by GSLV-MKII  thus augurs well for the Indian economy. ISRO has already lined up as many as ten satellites for launch by means of GSLV-MKII which will also boost India’s second mission to moon, Chandrayaan-II, in 2017. In addition, GSLV-II is expected to propel India’s futuristic deep space planetary probes including a follow on mission to the Red Planet, which is now being explored by India’s first successful mission to Mars, Mangalyaan.

  The success of GSLV-MKII is definitely a slap in the face of the notorious technology denial regime spearheaded by USA. In fact, way back in 1992, USA had prevented a thoroughly weakened Russia—in the aftermath of the disintegration of the Soviet Union—from honouring its commitment of transferring the cryogenic engine technology to India. The logic of US was that the sensitive cryogenic engine technology is a dual use system and its transfer is prohibited under the provisions of the so called Missile Technology Control Regime(MTCR). But then, on account of the complexities involved in handling propellants at extremely low temperatures, a cryogenic propulsion system cannot be a candidate for driving a strategic missile. Following this unsavoury development, ISRO decided to take up the challenge of developing a cryogenic propulsion technology literally from ground zero. And it must be said to the credit of the Indian space agency that it left no stone unturned in realising the dream of a home-grown cryogenic engine stage.

Meanwhile, ISRO Chairman A.S.Kiran Kumar has revealed that once commissioned, the services of GSLV-MKII will be offered on commercial terms for launching the satellite payloads of international customers for a fee. Describing GSLV-MKII  as a good candidate for commercial payloads, Kumar made it clear that ”ISRO will have to repeat the launch success of its GSLV-MKII to gain the confidence of satellite owners”.

As it is, Antrix Corporation, the Bangalore-based commercial arm of the Indian space programme, has already made modest forays in the multi-billion dollar, international market for launching satellites by  positioning PSLV as a reliable  and cost-efficient vehicle for delivering light-weight  satellite payloads into a variety of orbits. Till now the PSLV has launched 45 satellites belonging to customers from 19 countries on commercial terms.  The introduction of GSLV-MKII in the near future, followed by GSLV-MKIII thereafter, would considerably  expand and enhance the scope of the satellite launch service offered by Antrix. But then a limiting factor in the rapid expansion of the Indian satellite launch service business would be the solitary launch complex in the form of SDSC under the command of ISRO. Clearly India willneed to build a second space launch centre to step up the frequency of space missions. China, which already operates three land-locked launch centres, is now edging closer to commissioning its ultra-modern, coastal launch station at Wenchang in Hainan island. India will also need to encourage the formation of industrial consortiums capable of building and delivering satellites and launch vehicles in a ready to use condition. For staying competitive in the multi-billion dollar global space market is certainly no child’s play

The Indian defence forces willdefinitely stand to benefit from the 27  August GSLV-MKII mission that launched the cuboid shaped  GSAT-6 satellite, designed for a mission life of nine years. The digitalmultimedia broadcasting capability of this satellitethat  features the first of its kind large unfurlable S-band antenna with a diameter of six metres, will come in handy for the Indian defence forces keen on getting  information of strategic importance in a reliable, secure  manner and on a real time basis. The digital compression technique featured by GSAT-6 makes for its vastly enhanced data carrying capability.

The S-band  antenna of GSAT-6 would be utilised for five spot beams meant to cover the Indian mainland. The advantageous aspect of spot beams is that they exploit the frequency reuse scheme to increase frequency spectrum utilisation efficiency. The satellite also carries a national beam in C-band for authorised, strategic users. Yet another advanced feature of GSAT-6 is its 70 V bus which is featured for the first time in an Indian communications spacecraft.

Significantly,this high-powered satellite has a built-in capability to communicate with the small, hand-held terminals. The capability of GSAT-6 for two-way transmission of voice, video and data in a secure mode fits in well with the strategic communications philosophy of the Indian defence forces.This feature would be particularly beneficial for the armed forces keen on getting a holistic battlefield view . The potentials of GSAT-6 can also be harnessed for boosting the rapid strike capability of defence forces through the timely acquisition of the relevant information. For the defence forces operating in remote and difficult to reach areas, the GSAT-6 would enable establishing a hassle free communication link. What’s more, the GSAT-6 capabilities can also be exploited for strengthening the network-centric warfare strategy.

On another front GSAT-6 will serve as a platform for developing technologies such as demonstration of large unfurlable antenna in a space platform as well as  handheld ground terminals  and network management techniques  that could  be used in futuristic  satellite-based communications applications. Moreover, inputs provided by GSAT-6 would be a precious asset to design and develop high-capacity, futuristic digital multimedia satellites. ISRO is also planning to launch a follow-on GSAT-6A satellite with similar features and capabilities.

GSAT-6 is the 25^th geostationary communications satellite designed and developed by ISRO. After its commissioning, preceded by in-orbit manoeuvres and testing, GSAT-6 will join the group of India’s other operational geostationary satellites. Once fully operational, GSAT-6will also be harnessed for societal applications including disaster mitigation and emergency response. The GSAT-7 satellite also called Rukmani  launched in 2013 was India’s first full-fledged defence satellite that now serves as the exclusive space platform of the Indian navy. With this advanced, multi-band satellite at its command, the Indian navy is finding it easier to enhance its situational awareness in the Indian ocean region.