New Delhi: ISRO’s Navigation with Indian Constellation (NAVIC) is struggling because of failing atomic clocks, satellites that did not reach their intended orbits, and defunct satellites that have exceeded their planned mission duration. The Minister of State for Space, Jitendra Singh has responded to a question on the status of NAVIC posed in the parliament. 11 satellites have been deployed so far, out of which four are continuing to provide position, navigation and timing (PNT) services, with four satellites being used for one-way message broadcasts. One satellite is decomissioned, with two satellites being unable to reach their intended orbits.
In a similar update last year, it was revealed that three of the satellites had failed, leaving four operational satellites in the constellation. Only four are required to provide PNT services, but if any more satellites fail, then the service will be disrupted. Around 8,700 trains in the country are equipped with NAVIC, with plans to extend the tracking to 12,000 trains. These trains are using NAVIC along with other Global Navigation Satellite System (GNSS) services. The most recent launch for the NAVIC constellation occurred on 15 January, with the GSLV rocket performing flawlessly. After deployment though, the satellite could not reach its intended orbit.
ISRO to launch a NAVIC satellite every six months
ISRO plans to launch the NVS-03 satellite by the end of 2025, and subsequently the NVS-04 and NVS-05 satellites in intervals of six months. These are the second-generation navigation satellites that contain atomic clocks sourced from Europe, as well as indigenously developed rubidium clocks. These clocks are failing on the navigation satellites, a problem that affects not just NAVIC, but also Europe’s Galileo constellation. ISRO plans to launch a total of five second-generation satellites. The first of these was launched by the GSLV-F12 mission in 2023. The constellation was earlier called the Indian Regional Satellite System (IRNSS).