India's first navigation satellite readies for launch

The Indian rocket that at midnight will deliver the country's first navigation satellite is being readied for its mission with its second stage getting fuelled at Sriharikota, a senior official at Indian space agency said.

"The countdown is progressing well and the filling of the liquid fuel in the second stage is going on fine. The weather is good and we do not see any hitch in the mission," the official at the Indian Space Research Organisation (ISRO) told IANS Monday.

The 64.5 hour countdown began at 7.11 a.m. Saturday.

The 44-metre-tall Polar Satellite Launch Vehicle-XL (PSLV-XL) weighing 320 tonnes at lift-off is a four-stage rocket alternatively powered by solid and liquid propellants.

The solid fuel hydroxyl-terminated-poly-butadiene comes readily cast while the liquid fuel - unsymmetrical dimethyl-hydrazine-hydrate and 25 percent of nitrogen tetroxide for second stage and mono-methyl-hydrazine and mixed oxide nitrogen for fourth stage - are filled during the countdown.

Around 20 minutes into the launch, the PSLV-XL will eject the 1,425 kg IRNSS-1A (Indian Regional Navigation Satellite System-1A) at an altitude of 501 km.

The satellite is intended to provide terrestrial, aerial and marine navigation services and help in disaster management. The system is similar to the global satellite positioning (GPS) of the US and other countries.

The satellite, with a lifespan of around 10 years, is one of the seven constituting the IRNSS system developed by India and designed to provide accurate position information service to users within the country and up to 1,500 km from the nation's boundary, ISRO said.

The entire IRNSS system is expected to be in place by 2015 and the project is expected to cost around Rs.1,420 crore.

The service area can be expanded by adding more satellites, ISRO officials said.

The IRNSS will provide two types of services - standard positioning service and restricted service. The former is provided to all users and the later is an encrypted service for authorised users.