Space NavIC Setback: Failure of Atomic Clock on IRNSS-1F Context: The last working atomic clock on IRNSS‑1F stopped functioning on 13 March 2026, according to Indian Space Research Organisation. This failure weakens India’s regional navigation system NavIC, which relies on atomic clocks to provide accurate positioning, navigation, and timing (PNT) services. Role of atomic clocks Atomic clocks enable satellites to calculate precise signal timing, which is essential for determining location accurately. IRNSS-1F, launched in March 2016, completed its 10-year design mission life on 10 March 2026, though the satellite can still provide one-way broadcast messaging services. After the latest failure, only 3 satellites have working atomic clocks. The original atomic clocks used in NavIC satellites were imported from SpectraTime. NavIC provides navigation services over India and up to 1,500 km beyond its borders, unlike global systems such as Global Positioning System. ISRO plans to deploy new satellites with indigenously developed rubidium atomic clocks.NVS‑01 (May 2023) – carries India-made rubidium clock. Navigation with Indian Constellation (NavIC) To meet the positioning, navigation and timing requirements of the nation, ISRO has established a regional navigation satellite system called Navigation with Indian Constellation (NavIC). NavIC was erstwhile known as Indian Regional Navigation Satellite System (IRNSS). NavIC is designed with a constellation of 7 satellites and a network of ground stations operating 24 x 7. Three satellites of the constellation are placed in geostationary orbit, at 32.5°E, 83°E and 129.5°E respectively, and four satellites are placed in inclined geosynchronous orbit with equatorial crossing of 55°E and 111.75°E respectively, with inclination of 29° (two satellites in each plane). The ground network consists of control centre, precise timing facility, range and integrity monitoring stations, two-way ranging stations, etc. NavIC SPS signals are interoperable with the other global navigation satellite system (GNSS) signals namely GPS, Glonass, Galileo and…
