Overview
- ISRO said IRNSS-1F’s imported atomic clock stopped on March 13, days after the satellite completed its 10-year design life, and the craft will only support one-way messaging.
- Only three satellites now provide Position, Navigation and Timing—IRNSS-1B, IRNSS-1L and NVS-01—below the four required for a 3D fix, according to ISRO officials and parliamentary replies.
- Earlier clock failures across multiple first-generation spacecraft traced to Swiss-made rubidium units have crippled a significant share of the constellation.
- The second-generation NVS-02 could not raise its orbit in 2025 due to a connector issue that prevented engine ignition, leaving NVS-01 as the lone satellite flying an indigenous rubidium clock.
- Planned NVS-03/04/05 launches to rebuild coverage have slipped following recent PSLV anomalies, increasing risk to services that use NavIC for rail tracking, disaster alerts and marine or vehicle navigation.