People's Democracy

(Weekly Organ of the Communist Party of India (Marxist)


No. 31

July 31, 2011


PSLV Success, ISRO Still in Trouble




ISRO’s latest space mission on board the Polar Satellite Launch Vehicle (PSLV) C-17 has been an unqualified success. Following a textbook launch on July 15, from Launch Pad 2 at the Satish Dhawan Space Centre in Sriharikota, the GSAT-12 communications satellite was accurately placed in its planned geo-synchronous orbit after a series of manoeuvres and has since commenced operations. The PSLV C-17 mission has been a welcome boost of confidence and a huge relief to the Indian Space Research Organization (ISRO) which has been reeling under the pressure of two earlier failures of its Geostationary Satellite Launch Vehicle (GSLV).


With the success of C-17, the eighteenth one of a total nineteen launches, the PSLV has clearly come into its own and established itself as the reliable workhorse of ISRO. Yet very troubling questions remain for ISRO and for India. These arise from the different capabilities of the PSLV and the GSLV in terms of the payloads they can carry and the orbits these can be placed in, which in turn imply major differences as regards the kinds of services provided and gaining market share in international commercial space-based services. The PSLV has numerous positives, and will continue to serve India well in the coming years, but ISRO and India will not achieve their space goals nor realise their true potential until  the GSLV issues are resolved.




India’s space programmes have historically been far more development oriented compared to those of other major space-faring nations, not excluding the erstwhile Soviet Union which eschewed manned missions to the Moon on the grounds that they were not socially useful. India’s stance was not just making a virtue of necessity, being a poor developing country. The heavy development orientation of the Indian space programme was a conscious choice of its founders under the Nehruvian rubric of providing an impetus to science and technology, building self-reliant capabilities and maximising benefits to social welfare. ISRO therefore focused on satellites for weather readings, remote sensing to survey natural resources and infrastructure, and for communications which, in earlier years, meant mainly extending the reach of public service television carrying developmental information and messages, carrying educational programmes, and later for telemedicine and other rural outreach services.


The PSLV series with its first launch in 1993 was the direct result of this vision of India’s requirements from its space programmes. The initial goal was to enable launch of satellites into sun-synchronous orbits (SSO), used for ISRO’s IRS (Indian Remote Sensing) remote sensing series, which till then India could achieve only through launches aboard Soviet rockets. For a considerable period, PSLV’s capability remained limited to launching relatively small satellites in the range of 600 kg to 1900 kg upto low-earth orbits (LEO) of  300-2000 km above the Earth, with sun-synchronous orbits (SSO) usually being in the same range but at higher inclination or so-called “polar” orbits. Incidentally, except for the moon missions, all human space flights have been in LEO or sub-orbital altitudes. In LEO with low inclination or “equatorial” orbits, a satellite can complete one orbit around the Earth in about 90 minutes and can make several “passes” per day over any particular spot and can be effectively used for remote sensing or even for certain types of surveillance. LEO can also be used for communications but if all-day real time capability is required, this will require a constellation of several satellites. This is the reason why early ISRO communication satellites could provide services only at certain times of the day.


ISRO’s PSLV therefore provided limited but effective capability within a certain range of applications including communications. PSLV has been used to launch a total of 44 satellites to date including 23 for other countries including academic, observational, remote sensing and student-project micro-satellite payloads.


But when it came to intensive communication requirements for round-the-clock services such as television including direct-to-home services and telephony, ISRO and India have had to depend largely on the launch capabilities of others especially the Russians and the Europeans from their launch pad in Kourou in French Guiana. This is because such services call for larger and therefore heavier satellites, usually 3000 kg or more, placed in geo-stationary or geo-synchronous earth orbits (GEO) at around 35,000 km above the Earth directly over the equator. Satellites in such orbits appear motionless or stationary to an observer on the ground, and antennae tracking them can be pointed to a fixed position and do not have to move. The basic PSLV is not powerful enough to lift such heavy satellites. And the GSLV or Geosynchronous Satellite Vehicle has had repeated failures in one system or another especially in the indigenous cryogenic engine.


So far India has managed to cope with this lacuna in indigenous capability through clever upgradation of the PSLV. Apart from the basic version of the PSLV, the PSLV-CA or “core alone” version without the strap-on booster rockets was developed for heavier lifts to LEO. But a major breakthrough was achieved with the development of the PSLV-XL or extended version which had larger strap-on booster rockets. It was this rocket that was used in the Chandrayan mission by PSLV-C11. The latest C-17 launch almost replicated the Chandrayan trajectory in first reaching the Geo-stationary Transfer Orbit (GTO), an exaggerated elliptical orbit with lowest altitude of 284 km and highest altitude of 21,000km, from where boosters were fired by C-17 to reach the GEO while C-11 catapulted the vehicle towards the moon.    


But this cannot be a long-term arrangement. The GSAT-12 communications satellite launched by PSLV C-17 weighed only about 1400 kg. ISRO showed major inventiveness in adapting the satellite, urgently required in order to replace INSAT-3E which was reaching the end of its life, to carry several additional transponders compared to what it was designed for. The failed GSLV launch of December 2010 was carrying a satellite weighing over 2300 kg, and planned future versions of the GSLV are expected to be able to launch satellites of over 5000 kg and eventually 10,000 kg satellites which would put India and ISRO in the top drawer of nations with such launch capabilities.




This is not just a matter of national prestige. ISRO’s difficulty in acquiring reliable heavy launch capabilities has left huge gaps on two counts. First in terms of a severe shortage of transponders for communications services. And second, not merely having to spend additional funds in launches by other international launch service providers but also, and perhaps more importantly, missing out on the commercial opportunities India hopes to tap into in the lucrative launch market.     


After the two successive GSLV failures of 2010, and consequent upon existing satellites having reached the end of their design lives, the number of transponders India has in space has drastically come down from 211 to 175, that too with GSAT-8 having added as many as 24 transponders in 2007. 


The government had projected a perhaps over-ambitious target of having 500 transponders available in space by the end of the XIth Plan (2006-11) but did not achieve even half that! GSAT-12 launched by PSLV C-17 would bring the total up to 187. The launch of GSAT-11 aboard the Ariane rocket slated for year-end would add a further 30 transponders but this is far below India’s requirement with a booming demand for satellite communication services. 


ISRO needs to urgently solve its problems with the GSLV. There is a risk at present of demoralisation and loss of confidence among ISRO scientists and engineers. Perhaps a closer look is needed at sanctioned budgets too. At present, ISRO conducts too many tests on the ground as indeed it had done for the previous GSLV launch and found everything all right only to have the actual launch go horribly wrong. There is no substitute for real conditions and, at the risk of a few more failures, the GSLV programme needs to be fully backed and even stepped up in terms of launches even if this costs more, because the losses will be much greater if ISRO does not come up with a reliable heavy launch capability soon.  Such commercial launch services are currently being provided only by Russia and the European Space Agency, and there is a long queue with both. This means considerable delay and higher costs in augmenting the numbers of transponders India needs. And ISRO in turn is losing that much opportunity to enter this market and provide such services itself.




Meanwhile ISRO, the Department of Space and the government as a whole also need to address another opportunity that is being badly missed.       The GSAT-12 satellite carried several transponders to service what may be termed ISRO’s or the government’s own in-house needs in tele-medicine, tele-education, village resource centres and disaster management support services. But how effectively are these services actually being used, and how well are they integrated into the developmental programmes which they were expected to augment and qualitatively upgrade?  


India already has among the world’s largest constellation of remote sensing satellites and has now begun attracting buyers for data generated, including from advanced countries. But India’s own internal utilisation remains abysmally poor.


In a recent report, the Comptroller and Auditor General (CAG) has pointed out that almost 90 per cent of the images and data delivered by ISRO satellites are not used! This despite their obvious importance, apart from resource mapping, for infrastructure planning and development in roadways, land use, town planning, crop monitoring, coastal erosion and myriad other important applications. CAG lamented the fact that the main data processing facility at the National Remote Sensing Centre in Hyderabad is unable to generate images and other data quickly, often rendering such data redundant. CAG had also highlighted that a project to map degraded or “waste” lands had been delayed by many years even while government agencies were decrying the absence of such data! And ISRO chairman K Radhakrishnan was forced to admit that the CAG criticism was spot on! Other commentators have pointed out that US remote-sensing satellite services typically use and deploy around 90 per cent of the images and data they gather.


It is one thing to bemoan the lack of capability in commercial satellite services which are expected to become available through the GSLV. But it is equally important that ISRO and government re-focus attention on the core areas of developmental applications for which the PSLV and its low-earth orbit satellite services were conceived in the first place.