Isro confirms failure of NavIC satellite IRNSS-1F after atomic clock malfunction

India’s indigenous navigation satellite system—Navigation with Indian Constellation (NavIC) suffered one of the major setbacks after one of its four operational satellites reported a failure at the end of 10 years since its launch, according to officials from the Indian Space Research Organisation (Isro). 

The Indian Regional Navigation Satellite System (IRNSS) satellite IRNSS-1F, launched on March 10, 2016, has failed after its last functioning atomic clock malfunctioned, according to sources in the Department of Space. The satellite had been operating with only one of its three onboard atomic clocks.

At least four indigenous navigation satellites must remain fully operational for the NavIC system to deliver navigation services to the public and government users, including the railways and the military.

“On 13th March 2026, the procured on-board atomic clock stopped functioning. However, the satellite will continue to function in-orbit for various societal applications to provide one way broadcast messaging services,” Isro said in an official statement on Friday night.

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“IRNSS-1F satellite launched in March 2016 has completed its design mission life of 10 years on 10th March 2026,” the statement posted on the Isro website said.

Isro launched about 11 satellites since July 2013 for nearly Rs 2,250 crore NavIC system, out of which six satellites have failed primarily due to the defective imported atomic clocks in the initial years, due to orbital issues. 

Last year, the Union government informed Parliament that only four of the 11 satellites launched for the NavIC system were fully operational for positioning, navigation, and timing services, while the remaining satellites were being used in a limited or sub-optimal capacity.

“As of now, 11 satellites have been put in orbit. Some of them are not functioning. At present, four satellites are providing Position, Navigation and Timing (PNT) services, four satellites are being used for one way message broadcast, one satellite got decommissioned after its end-of-life service. Two satellites could not reach the intended orbit,” Minister of State for the PMO, Jitendra Singh, said in a reply in the Lok Sabha on July 23, 2025.

With the reported failure of IRNSS-1F, only IRNSS-1B, IRNSS-1L and IRNSS-1J (NVS-01) are currently functional for NavIC positioning, navigation and timing (PNT) services. The malfunction of all atomic clocks on IRNSS-1F brings the number of NavIC satellites lost due to clock failures to six out of the 11 launched for the system.

“Location services provided by the NavIC system in India are going to be affected,” space department sources said.