The navigation satellite, NVS-01, was successfully launched by the Indian Space Research Organisation (ISRO) on May 29, 2023 from the second launch pad at the Satish Dhawan Space Centre (SHAR), Sriharikota in Andhra Pradesh. The satellite, weighing about 2,232 kg, was put into a geosynchronous transfer orbit (GTO). NVS-01 is the first of the second-generation satellites envisaged for the Navigation with Indian Constellation (NavIC) services.
About the Satellite
The Indian Regional Navigation Satellite System (IRNSS) is operationally known as Navigation with Indian Constellation (NavIC). It took the GSLV-F12 just over 18 minutes to put NVS-01 into the GTO of 173 km. Further orbit-raising maneuvers (circularisation) was later done to bring the satellite to its final position. It would provide accurate real-time positioning and timing services over India and a region extending approximately 1,500 km around the Indian mainland. Its signals are designed to provide user position accuracy better than 20 m and timing accuracy better than 50 ns. This system would benefit the nation as it would add to India’s regional navigation system and provide accurate and real-time navigation.
The fully deployed NavIC consists of seven satellites in geosynchronous/inclined geosynchronous orbits. It also has a network of ground stations operating round the clock. Three satellites of the constellation were placed in the geostationary orbit and four satellites were placed in the inclined geosynchronous orbit. The ground network consists of a control centre, precise timing facility, range and integrity monitoring stations, two-way ranging stations, etc. The satellite has a mission life of over 12 years, whereas the first-generation satellites in the constellation had a mission-life of 10 years.
Applications of NavIC
The key applications of NavIC include terrestrial, aerial, and maritime navigation, precision agriculture, geodetic surveying, emergency services, fleet management, location-based services in mobile devices, orbit determination for satellites, marine fisheries, timing services for financial institutions, power grids and other government agencies, internet of things (IoT)-based applications and strategic applications.
The satellite, NVS-01, is powered by two solar arrays, capable of generating power up to 2.4kW and a lithium-ion battery that would support payload and bus load during eclipse. The satellite would replace the IRNSS-1G satellite launched in 2016.
GSLV Mark II (GSLV MkII) is the launch vehicle developed by India, to launch communication satellites in GTO using cryogenic third stage. Initially, Russia provided the cryogenic technology to India. However, since 2014, the technology was successfully developed and inducted in India as well. This would be a return flight mission for the GSLV launch vehicle, which has carried the next generation NavIC satellite.
According to ISRO, the GSLV-F12 is the 15th flight of India’s GSLV and the ninth flight with indigenous cryogenic stage. This is the sixth operational flight of GSLV with indigenous cryogenic stage.
Notably, in August 2021, GSLV launch had failed when a malfunctioning valve led to insufficient pressure in the liquid hydrogen tank in the cryogenic upper stage, which resulted in the stage not getting ignited.
The NVS-01 has carried navigation payloads L1, L5, and S bands. For the first time, an indigenous atomic clock was also flown in NVS-01. The L1 navigation band encompasses indigenously developed rubidium frequency standard (RAFS) atomic clock which is the heart of the satellite, and which would act as a stable frequency reference for the navigation payload. (The L1 navigation band is popular for providing position, navigation, and timing (PNT) services for civilian users and for interoperability with other Global Navigation Satellite System (GNSS) signals.) (The space-qualified rubidium atomic clock has been indigenously developed by the Space Applications Centre, Ahmedabad. It is an important technology which only very few countries in the world possess.)
The vehicle also used the new 4m Ogive payload fairing—the shield within which the satellites are housed to protect them from atmospheric friction and heat—capable of carrying bigger payloads.
ISRO’s Future Launches
ISRO has a very hectic year with the launch of the first solar mission, the third lunar mission, and the test vehicle under the Gaganyaan mission, slated for the later part of 2023. ISRO also plans to launch the weather satellite INSAT-3DS and NASA-ISRO SAR (NISAR) satellite with GSLV.
ISRO’s schedule also includes a test at an altitude of 14 km where systems would be destroyed to check how the crew could be saved in case of a mishap. The other systems for Gaganyaan are being tested at various centres of the space agency. The unmanned Gaganyaan mission has been planned for 2024.
ISRO is also working on designing a new rocket that could carry much higher luggage. It is also upgrading the Launch Vehicle Mark-III (LVM3) rocket to lift up to 5.5 tonnes from the current four-tonne capacity.
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