ISRO’s NavIC Satellite IRNSS-1F Atomic Clock Fails After Completing 10-Year Mission
ISRO's IRNSS-1F atomic clock fails after 10 years, yet NavIC continues supporting navigation and messaging services.
India’s indigenous navigation satellite, IRNSS-1F, has suffered an atomic clock failure after completing its full 10-year mission life, the Indian Space Research Organisation (ISRO) confirmed on Monday. Despite the malfunction, ISRO stated that the satellite will continue to support certain services, including one-way broadcast messaging.
The IRNSS-1F, part of India’s Regional Navigation Satellite System (IRNSS), also known as NavIC, was launched on March 10, 2016. Department of Space sources reported that the satellite’s last functioning atomic clock stopped working on March 13, 2026. “However, the satellite will continue to function in orbit for various societal applications to provide one-way broadcast messaging services,” the sources added.
NavIC, developed entirely by ISRO, provides navigation services for civilian use as well as government agencies, including Indian Railways and the military. The satellite network relies on highly precise atomic clocks to calculate positions accurately; even minor clock errors can result in positional inaccuracies of several hundred kilometres. IRNSS-1F’s atomic clock failure marks another challenge in the programme, which has seen multiple satellites affected by clock or orbital issues.
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Since the launch of the first NavIC satellite in July 2013, ISRO has deployed 11 satellites in the constellation, of which six have failed due to defective imported atomic clocks or other technical issues. The programme, estimated to have cost around ₹2,250 crore, continues to provide critical positioning, navigation, and timing (PNT) services. Following IRNSS-1F’s failure, the remaining operational satellites providing PNT services are IRNSS-1B, IRNSS-1L, and IRNSS-1J (NVS-01).
NavIC’s services are widely used in India, including by roughly 12,000 trains for tracking purposes, with about 8,700 trains equipped with NavIC alongside other global navigation satellite system (GNSS) constellations. The system was first conceptualised in 1999 after the Kargil War, when Indian defence forces faced limitations using the US-owned Global Positioning System in conflict zones.
Despite the setback, ISRO emphasized that IRNSS-1F will remain in orbit and continue to contribute to messaging services, highlighting the resilience of India’s homegrown navigation infrastructure as it supports both civilian and strategic applications.
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