ISRO must make the GSLV Mk II operational as quickly as possible and move onto the GSLV Mk III. After the twin setbacks of 2010, this may indeed be ISRO’s turnaround year.

The Indian Space Research Organisation (ISRO) has enjoyed some major triumphs in the highstakes space exploration enterprise. At other times, it has plumbed the depths of despair. One high point was the launch of Chandrayaan-1, India’s first moon probe, on October 22, 2008. Although the mission was not an unqualified success, it put the national flag on the surface of the moon and was the first spacecraft to detect signs of water on earth’s nearest neighbour. No mean achievement. Soon thereafter, ISRO announced a low-cost programme intended to launch the first Indian spacecraft carrying an Indian as early as 2016. It was hoped that a planned series of human spaceflight missions would culminate in an Indian walking on the moon’s surface around 2020. The world’s media began to speculate about another space race brewing—this time between China and India. It all seemed too good to be true, and so it turned out.

April 15, 2010, was the day set for a vital test of India’s most advanced rocket, the geosynchronous satellite launch vehicle (GSLV), at the Satish Dhawan Space Centre at Sriharikota. That’s when things began to unravel. It had been an eagerly awaited mission because it was the first to feature indigenous cryogenic capability—technology painstakingly developed by ISRO in the wake of stringent US sanctions, ostensibly because it could be “misused” to power long-range missiles. However, after a flawless lift-off, the crucial cryogenic upper stage of the GSLV-D3 underperformed and the costly rocket went spinning out of control. And on Christmas Day, the same year, the GSLV-F06 rocket was launched, but it failed to develop its rated thrust, and veered off course, rendering its destruction unavoidable. After detailed investigation, ISRO claims to have uncovered the causes of the back-to-back failures and is getting ready to move on. But the memories of these fiascos are yet to be erased.

Giant GSLV

Why is the GSLV so important? ISRO is understandably keen to acquire the ability to launch heavy satellites entirely on its own. This would give it a thick slice of the lucrative satellite launch cake. The powerful GSLV can inject a communications satellite into geosynchronous transfer orbit (GTO) from where the satellite’s on-board propulsion system can lift it to its intended geosynchronous earth orbit (GEO), almost 36,000 km from earth. ISRO’s ambitions of sending Indian astronauts into space will remain a pipe dream as long as a reliable launch vehicle of the GSLV class is not available. Just now it isn’t. It will probably take several consecutive successful missions for the GSLV to evolve into a reliable unmanned launch system. And human-capable spacecraft cannot have a failure rate of more than two per thousand flights. ISRO also needs to work on areas like thermal protection; life support and crew escape systems. The present schedule calls for about two launches per year, so getting the GSLV “man-rated” could take several more years. Therefore, the buzz now emanating from ISRO, points to a more realistic 2020 target for an indigenous astronaut launch; contingent on the GSLV quickly tasting success.

In contrast, the GSLV’s predecessor—the polar satellite launch vehicle (PSLV)—is a major success story. It has already notched 20 continuous successful flights. Using PSLV rockets and some foreign launch facilities, ISRO has fashioned two major satellite constellations. The Indian National Satellite (INSAT) System, the largest national communications system in the Asia-Pacific region, consists of geosynchronous satellites that satisfy the telecommunications, broadcasting, meteorology and search-and-rescue needs of India. The Indian Remote Sensing (IRS) Satellite System, useful for earth observation, is the largest constellation of civilian remote sensing satellites anywhere in the world. ISRO shortly intends to launch the first satellite in a third constellation—the Indian Regional Navigation Satellite System (IRNSS). When the seven-satellite IRNSS becomes fully functional around 2014, it will be India’s equivalent of the global positioning satellite (GPS) system and make the country completely selfreliant in satellite navigation services.

However, launching communication satellites using the PSLV is rather uneconomical since it can only lift 1,060 kg into geosynchronous transfer orbit (GTO). A large satellite is vastly preferable. Most advanced communications satellites nowadays are of the six-tonne class, enabling a large number of transponders and other communications equipment to be included. That is why ISRO hopes to launch the next GSLV Mk II, with an indigenous cryogenic third stage, by October 2012. However, the more advanced and capable GSLV Mk III will have to wait till at least 2014. That would be able to orbit communications satellites weighing up to five tonnes. Alternatively, it could be used to deliver more than 10 tonnes into low earth orbit.

The demand for transponders in the country is increasing by the day and since ISRO has barely half its planned transponders in orbit currently, it is forced to acquire extra ones on lease. GSAT-11, ISRO’s biggest ever advanced communications satellite with 32 transponders in the Ka and Ku bands, is planned to be launched by 2014. However, the much-delayed launch of the dedicated communications and surveillance satellite Rohini, intended for the Indian Navy, may not take place till next year. Only after that can the Indian Air Force and Indian Army hope for their own satellites.

Outward Bound

ISRO also has ambitious space exploration plans. India’s second mission to the moon Chandrayaan-2, planned in 2014, is weighty enough to be blasted off by a GSLV rocket, unlike Chandrayaan-1 which was launched using a PSLV. At least two GSLV rockets will be tested at an interval of six months before the third is entrusted with the moon exploration payload. Chandrayaan-2 will have an Orbiter and Lander-Rover module. ISRO will be responsible for the Orbiter and Rover, while Roskosmos of Russia will be responsible for the Lander. The Rover will travel on wheels across the lunar surface, do a chemical analysis of soil samples, and relay the data back to earth via the Orbiter.

Before the moon, ISRO has Mars on its radar. The Mars Orbiter mission is intentionally light, low-cost and simple in payload. Since Mars launch windows come around just once every 26 months, ISRO hopes to seize the next chance in November 2013, using the most powerful version of its workhorse PSLV rocket—the PSLV-XL. The Mars Orbiter, with nearly 25 kg of scientific payload on-board, will be placed in an elliptical orbit of 500 x 80,000 km around Mars. It is likely to focus on the climate and geology of Mars and the origin, evolution and sustainability of life on the planet. ISRO has also formulated preliminary plans for a mission to Venus in 2015. The aim would be to study its atmosphere and examine the origin and evolution of the planet.