A GSLV rocket carrying navigation satellite NVS-02 lifted off from the Sriharikota spaceport on Wednesday, January 29, 2025, marking ISRO's 100th mission.
The mission was also the first for ISRO Chairman V Narayanan, who assumed office on January 14, 2025. It is ISRO's maiden venture this year.
As the 27.30 hour countdown concluded, the 50.9 metre tall rocket, emanating thick fumes on its tail, lifted off majestically from the second launch pad at a prefixed time of 6.23 am on Wednesday.
The Geosynchronous Satellite Launch Vehicle (GSLV-F15) follows the GSLV-F12 mission which successfully carried navigation satellite NVS-01, the first of the second generation satellites on May 29, 2023.
Venkatachari Jagannathan reports:
India on Wednesday in textbook style orbited its second of its second generation navigation satellite code named NVS-02.
In the process the milestone of 100 rocket launches from the country's Sriharikota rocket port has also been achieved.
With the new navigation satellite, ISRO is filling up part of the void in India's navigation satellite constellation -- Navigation with Indian Constellation or NavIC or colloquially known as the Indian GPS.
At 6.23 am, the 50.9 metre tall and weighing 420.7 ton Geosynchronous Satellite Launch Vehicle-F15 (GSLV-F15) laden with the 2,250 kg NVS-02 blasted off from the second launch pad at the rocket port in Sriharikota.
The thick orange flame at its tail the rocket went up with a deep growl while lighting up the early morning skies over Sriharikota with orange hue.
Just over 19 minutes into the flight the satellite placed into a Geosynchronous Transfer Orbit (GTO). From there NVS-02 will be taken up further to Geostationary Orbit.
Speaking at the mission control centre ISRO Chairman Dr V Narayanan said: "I am extremely happy to announce the first launch of 2025 was successfully accomplished."
Dr Narayanan said the NVS-02 satellite was injected with a very minimal level of dispersal. The NavIC satellite is evolving, he added.
ISRO till date has developed six rockets and till date cumulatively it has lifted 548 satellites, Dr Narayanan explained, weighing about 120 tons including 433 satellites that weighed 23 tons.
The GSLV-F15 launch was the 100th rocket launch from Sriharikota taking into account all its rockets other than sounding rockets -- Satellite Launch Vehicle-3 (SLV3-4 missions), Augmented Satellite Launch Vehicle (ASLV-4 missions), Polar Satellite Launch Vehicle (PSLV-62 missions), GSLV (16 missions), Launch Vehicle Mark 3 (LVM3 earlier GSLV-MkIII, 7 missions), Small Satellite Launch Vehicle (SSLV, 3 missions), Air Breathing Propulsion Project (ABPP) and Reusable Launch Vehicle -- Technology Demonstrator (RLV-TD) and two sub-orbital rocket launches by two private companies.
The NVS-02 will replace the Indian Regional Navigation Satellite System -1E (IRNSS-1E) satellite, part of the first generation satellite series. The long winding IRNSS is the old name for NavIC.
NavIC will provide accurate Position, Navigation and Timing (PNT) services to users in India and to the region extending about 1,500 km beyond the country's land mass.
As of now NavIC provides two types of services, namely, Standard Positioning Service (SPS) and Restricted Service (RS).
NavIC's SPS provides a position accuracy of better than 20 m and timing accuracy better than 40 ns (nano seconds) over the primary service area, ISRO said.
According to the Indian space agency, five second-generation NavIC satellites NVS-01/02/03/04/05 will augment NavIC's base layer constellation with enhanced features for ensuring continuity of services.
The NVS series will work along with earlier satellites in the L5 and S bands. The L1 band is only in NVS-01 and 02 satellites.
A minimum of four satellites are needed to get a navigation solution at any time and more to improve accuracy, Dr S Somanath told this correspondent prior to his retirement as ISRO chairman this month.
According to Dr Somanath, the remaining three second generation navigation satellites will be launched at an interval of six months.
The life of each satellite will be 10 to 15 years if there are no electronics failures.
The NVS series of satellites incorporates L1 band signals additionally to widen the services.
The first of the second generation NavIC NVS-01 was orbited on May 29, 2023 by a GSLV-F12 rocket.
One of the spin-off benefits of the IRNSS programme is the indigenous development of atomic clocks by India.
With imported clocks failing in some of the IRNSS satellites, India decided to develop its own atomic clocks saving about Rs 3 crore (Rs 30 million) per satellite.
Each IRNSS satellite carried three atomic clocks.
For the first time, an indigenous atomic clock was flown in NVS-01.
Dr Narayanan said the NVS-02 satellite has the second indigenous atomic clock, a shining example of Make In India efforts.
The NVS-02 uses a combination of indigenous and procured atomic clocks for precise time estimation.
According to Dr Somanath, there were no atomic clock failures during the past five years after the vendor made some corrections as suggested by ISRO.
The NVS-02 satellite uses both imported and India-made atomic clocks and they are compatible, Dr Somanath remarked.
ISRO said the NVS-02 satellite is configured with navigation payload in L1 (primary frequency band used by satellite constellations), L5 (used for high precision services) and S (commonly used in satellites) bands in addition to ranging payload in C-band like its predecessor-NVS-01.
NVS-02 satellite was designed, developed and integrated at ISRO's U R Satellite Centre with the support of other satellite-based work centres. The space agency said the navigation satellite will be used for strategic applications, terrestrial, aerial, and maritime navigation, precision agriculture, geodetic surveying, fleet management, location-based services in mobile devices, orbit determination for satellites, Internet-of-Things (IoT) based applications, emergency services and timing services.
Many mobile chipsets have NavIC signals now with the advent of L1 signal in the second generation Indian satellites. The L1 signals offer better location based services in the consumer segment.
Out of the seven IRNSS satellites that were orbited earlier, four are functional providing Position, Navigation and Timing (PNT) service and the remaining ones offer safety-of-life messaging services.
The full constellation of seven satellites is expected to be completed in coming years, according to the government.
"India is one of the select countries that have its own satellite navigation system," Dr Somanath said. "We have to increase the size of the constellation to nine to extend the range in the future."
Venkatachari Jagannathan can be reached at venkatacharijagannathan@gmail.com
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