Friday, June 26, 2009

Trajectory of space technology

India’s national programme could be coupled with an international collaborative framework

As India celebrates 60 years of Independence, the world space community observes the 50th anniversary of the launch of the Sputnik. The Indian space endeavour had its modest beginnings with the launch of a sounding rocket from Thumba on November 21, 1963. In the following four decades, the programme has made major strides. Its current capabilities encompass launch vehicles, satellites, developmental applications and space exploration, transforming the country into a pre-em inent space-faring nation.
The early inspiration for Indian space efforts came from the scientific community interested in research in geophysics and astrophysics. Jawaharlal Nehru’s approval for initiating space activities in India at the suggestion of space pioneer Dr. Vikram Sarabhai way back in 1962 was an act of extraordinary foresight and courage, particularly in the context of the newness and complexity of the technology and the high risks involved.
The vision of space that Dr. Sarabhai gave India is remarkable for its realism and pragmatism, unique for its deep insights into the socio-economic context of the country, and extensive in the level of detail and identification of different dimensions. The elements of the vision included the use of the space programme for societal benefit and enrichment, the development of high technologies, the creation of leadership, emphasis on self-reliance, the identification of new organisational structures, as well as the role of humans in space. Such an elaborate and carefully crafted vision, spread over a decade, helped the growth of a unique India-centric programme over the next three decades.
Three phases
The evolution of the programme beyond the period of vision took place in three distinct phases. The first phase involved demonstrating proof of concept ideas by the use of foreign space systems, the configuration of the ground system to suit special national needs, as well as working closely with the potential user community. The Satellite Instructional Television Experiment (SITE), using the American ATS-F satellite, with emphasis on rural areas and dealing with such subjects as family welfare, agriculture, primary education and teacher training, is one such example.
In the second phase, unique experimental systems were tried out to derive an end-to-end experience in the realisation of space systems where the potential of its use at the national level had already been clearly demonstrated in the proof of concept phase.
The building of two experimental earth observation satellites, Bhaskara-I and Bhaskara-II, that enabled India to acquire valuable experience in realising the capability for space-based imaging, and processing these on the ground through appropriate ground infrastructure, is a case in point. The Ariane Passenger Payload Experiment (APPLE) mission conducted in 1981 to gain experience in satellite communications is another example. This experimental phase also witnessed significant progress in the design and development of launch vehicles.
The realisation of India’s first launch vehicle SLV-3, an all-solid, four-stage rocket with a modest payload capability of 40 kg, followed by the ASLV with a 150-kg payload, were milestones. These early versions ultimately paved the way for the development of the current operational satellites and launch vehicles — the Polar Satellite Launch Vehicle (PSLV) and the Geo-synchronous Satellite Launch Vehicle (GSLV).
The Indian space programme today is a large, integrated programme, which is self-reliant and applications-driven, maintaining vital links to the user community and committed to excellence in scientific endeavours. The technological capabilities include building of state-of-the-art satellites as well as appropriate launch vehicles. India has established two major operational space systems.
The Indian National Satellite (INSAT) system, currently comprising nine satellites in orbit and with a capacity of 199 transponders in C, extended C and Ku bands, is one of the largest domestic satellite communication systems in the world. The design life of the most recent ones among these is 15 years.
The Indian Remote Sensing Satellite (IRS) system, with a constellation of seven satellites, comprises some of the best satellites in the world for generating information on natural resources. IRS represents a wide range of spatial resolutions from 1 km to better than a meter. Both the INSAT and the IRS employ unique Indian designs and a variety of sophisticated, indigenously developed technologies.
Space launch vehicles developed by India are aimed to provide autonomous launch capability to orbit these classes of satellites. The PSLV is well-proven through eight successive successful flights, and it provides the capability to orbit remote sensing satellites of the 1.4 tonne class in polar sun synchronous orbits. The GSLV, capable of launching the 2 to 2.5 tonne class INSAT satellites, has been operationalised with three successful flights in a row, making India one of six countries to demonstrate geo-stationary satellite launch capability. Because of the strict technology control regimes, the launch vehicle development had to depend solely on indigenous efforts.
Both the IRS and INSAT satellites have benefited the country in various areas of national development. INSAT satellites are the mainstay for TV broadcasting and provide connectivity to more than 1,100 TV transmitters. They network radio stations, provide rural area communications, business communications and tele-education and tele-medicine services. They are used to relay cyclone warnings, gather meteorological data, assist weather forecasting for emergency communication support during disasters and provide search-and-rescue support.
Imagery and data from the IRS satellites are used for vital applications such as locating zones of groundwater availability in habitations without access to drinking water, monitoring crops, providing advisories to coastal fishermen on potential fishing zones, planning watershed, rural development and wasteland management programmes, and disaster management support.
Manned missions
Another recent landmark is the Space Capsule Recovery Experiment (SRE-1), intended to demonstrate our capability to orbit a spacecraft to perform experiments in microgravity conditions and bring it back to earth, thus proving the technology of deorbiting and recovering objects from space. The SRE-1 provided valuable inputs for the design of future reusable launch vehicles and manned missions.
In the area of space science, recent highlights include developing a multi-wave length astronomy observatory (Astrosat) and the mission to the moon (Chandrayaan-1). Astrosat, with the capability to make observations over a broad band of electro-magnetic spectrum from visible, ultra-violet to X-rays, is planned for launch in 2008. Scientific data from this mission is expected to provide insights into some of the hottest and densest regions in the universe. The technology of the observatory itself is highly complex with high-precision pointing and the ability to slew the satellite to look at different regions in the sky.

Soaring high: The PSLV-C 8 vehicle on the launch pad in Sriharikota.
Chandrayaan-1 represents India’s foray into the domain of planetary exploration. Through this very first initiative, India is playing the role of a lead partner in a truly international cooperative effort. The scientific outcome of this mission will help improve the understanding of the origin and evolution of the moon.
The next major development in the field of launch vehicles will be the GSLV-Mk III with the capability to place a 4-tonne satellite into a geosynchronous transfer orbit. The realisation of the GSLV-Mk III, which draws considerably from the technologies of the previous PSLV and GSLV programmes, in the next two or three years will enable India to meet all its requirements in the context of heavier communication satellites with higher power and more capacity.
In the coming years one of the major tasks is to reduce the cost of space transportation by developing reusable air-breathing propulsion launch vehicles and recoverable systems. The Indian Space Research Organisation (ISRO) has taken the first steps in this direction. The futuristic communication satellites will call for operations in higher frequency band like Ka-band, optimisation of frequency channels through beam forming, switching and onboard regeneration. Some of these are planned to be experimented in the GSAT-4 mission. On the remote-sensing side, major developments of the future include space-borne synthetic aperture radars with all-weather capability and advanced ocean observation systems that will include ocean colour monitors for biological productivity studies, scatterometers and altimeters for physical oceanography.
ISRO recently announced plans for a manned mission. Many new areas of science and technology have to be developed for this purpose, including life support systems, space biology, reentry and safe recovery of astronauts. Expanding further the role of space, the Indian scientific community is studying lunar basing concepts, as well as missions to Mars and other planets. These activities could have a strong international collaboration and cooperative component. India’s capability and credibility in space will certainly qualify it to play the role of an important partner.
In a nutshell, the future of India’s space programme will certainly continue to have a core component to meet the social objectives with a policy of technology self-reliance. However, expanding the scope into futuristic application and space exploration could be taken up through increased international collaboration and a cooperative framework.
We are at a turning point in the history of space research and our unique national programme is eminently suitable to be coupled with a pragmatic international collaborative framework. This could be the best way to meet the country’s aspirations in space in the 21st century.
Dr. K. Kasturirangan, former head of India’s space programme and former ISRO Chairman, is Director, National Institute of Advanced Studies, Indian Institute of Science, Bangalore.

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