The failure of the PSLV C39 mission launched on 31 August by the Indian Space Research Organisation from Sriharikota to place Indian Regional Navigation Satellite System’s 1H satellite in geosynchronous orbit is a major setback for the country’s own navigation system modeled after the Global Positioning System (GPS) of the USA. IRNSS comprises a constellation of seven satellites to make it fully operational. IRNSS 1A was launched way back in mid-2013. Considering the life-span of a satellite of this kind is six to eight years, ISRO should have completed the series in the shortest possible time.
It has the capacity to launch PSLV missions once in three months and could have completed the IRNSS constellation in early 2015. Unfortunately, ISRO dragged its feet and strayed from its chosen path in search of pastures new. As a result, the last and the seventh in the series, IRNSS 1G, could be launched only in April this year, by which time the timekeeping system on board IRNSS 1A had failed completely. IRNSS 1H was to replace disabled IRNSS 1A but it failed to detach itself from the PSLV rocket. ISRO was planning to launch IRNSS 1I was in November as a spare satellite, followed by two more, IRNSS 1J and IRNSS 1K, next year to keep the constellation going uninterruptedly, but the failure of PSLV C39 mission has upset the schedule and it is not known when the constellation, named NAVIC by Prime Minister Narendra Modi, will become fully operational.
ISRO scientists believe NAVIC will become fully operational by November this year. Only then India could boast of having joined the exclusive club of countries having their own satellite navigation system. The USA is the leader in the field with its GPS having worldwide coverage. Russia comes second with its GLONASS having similar coverage. Europe is putting up its own constellation called Galileo and China is constructing BeiDou which has already put in place a regional service and it plans to achieve global coverage by 2020. All these systems use 28 to 35 satellites whereas NAVIC will provide regional coverage with a mini-constellation of just seven satellites. It will beam accurate navigation signals over India and up to 1,500 km from its borders.
By adding four more satellites, India too can have worldwide coverage. Its services include terrestrial and marine navigation, disaster management, vehicle tracking and fleet management, navigation for hikers and travellers, visual and voice navigation for drivers. Failure of the PSLV C39 mission was due to non-separation of the heat shield of the rocket which trapped with it the satellite. There was no design failure, say experts. Of the 41 PSLV launches so far, 39 were successful, giving it a success rate of 95.13 per cent, which compares favourably with the record of world space agencies.