ISRO's GSLV-F18 launch success revives NAVIC, but there's a catch...

On Saturday (October 31), Indian space agency ISRO executed a successful launch mission by placing navigation satellite NVS-03 into the designated orbit. In what was ISRO's third launch of the year, the GSLV-F18 lit up the midnight skies over Sriharikota, as the rocket carried the 2,250kg NVS-03 satellite into Geosynchronous Transfer Orbit(GTO), from where it will be moved to its final orbit by firing onboard engines.

"The satellite was successfully and precisely injected in intended orbit. With this, NAVIC (Navigation with Indian Constellation) has been restored to its minimum operational configuration, and Position, Navigation & Timing (PNT) services of the country have been restored. NAVIC is a strategic national asset, which provides us independent access to PNT," said ISRO Chief Dr. V. Narayanan in his post-launch address. Navigation with Indian Constellation (NAVIC) was envisaged as an Indian version of America's GPS or Russia's GLONASS or China's Beidou.

While GPS, GLONASS, Beidou provide global coverage, NAVIC is meant to serve civilian and defence users within Indian borders and 1,500kms beyond. NAVIC is a project of immense strategic significance, as it is meant to serves the Armed Forces and the civilians. The NVS-03 satellite carries an Indigenous Atomic clock, along with the procured Atomic clocks. It also includes L1 signal in addition to existing L5/S-band signals. "The solar panels of the satellite have been deployed and the spacecraft is in good health. The orbit raising of the satellite will be done in a week," confirmed DK Singh, Director of ISRO's UR Rao Satellite Centre.

NAVIC restored to minimum operational configuration, but there's a catch…

Theoretically, a bare minimum of four satellites are required for the functioning of NAVIC's core services. Right now, there are four NAVIC satellites believed to be capable of providing Positioning, Navigation & Timing services: first-generation satellites IRNSS-1B, IRNSS-1I; and second-generation satellites NVS-01 and the newly-launched NVS-03. Which is why ISRO announced that NAVIC has been restored to its minimum operational configuration of four satellites.

However, of these four, IRNSS-1B has lived longer than its expected life of 10 years, and could potentially fail anytime. If all goes well, IRNSS-1I could potentially function till 2028. NVS-01 has at least a decade of life ahead of it, if it functions as designed. NVS-02 was launched in January 2025, but the satellite got stuck in its initial orbit, as its onboard engines could not be fired for orbit raising. Stuck in its initial orbit, NVS-02 is of very limited use and cannot be considered as an operational one. Therefore, considering long-term functionality, only two satellites: NVS-01 and the new NVS-03 can be considered truly operational, because of the decade-long service that lay ahead of them.

How many NAVIC satellites would be ideal ?

If the Indian government wishes to revive and sustain NAVIC in a robust and reliable form, it must place at least three or more NVS-series satellites in orbit, all in quick succession. ISRO must launch NVS-04, NVS-05, and NVS-06 satellites, which can work together with the existing NVS-01 and the NVS-03. However, that is the basic requirement. To have higher reliability and robust capabilities, India would also have to build and launch backup satellites in the NVS-series.

Eventually, a fleet of six or seven satellites would have to be maintained for reliably operating a regional navigation system such as NAVIC. America's Global Positioning System (GPS), which supports trillion-dollar civilian and military applications worldwide, requires a fleet of 24 satellites in orbit for optimum performance, round-the-clock global coverage. Considering how crucial GPS is to the global economy, the US government maintains at least 30 GPS satellites in orbit at any given point of time.The six additional satellites are meant to ensure that the service remains reliable and robust, even when a few satellites fail or encounter unexpected glitches.

To meet its own national requirements, China operates a fleet of Beidou satellites, which serve as an alternative to America's GPS. While Beidou's global network requires a fleet of 30 satellites in orbit, around 35 satellites are believed to be in orbit. Likewise, India too needs to have a fleet of at least five NAVIC satellites and a backup satellite or two in orbit.