indias indigenous satellite navigation network has suffered a significant setback after one of its operational satellites stopped functioning following a decade in orbit. The development could affect the country’s Navigation with Indian Constellation (NavIC) system, which provides positioning and navigation services for both civilian and government applications.

The satellite IRNSS-1F, part of India’s Indian Regional Navigation Satellite System (IRNSS), reportedly failed after its last functioning atomic clock stopped working. The incident highlights ongoing technical challenges faced by the NavIC constellation since its deployment.

IRNSS-1F Completes 10-Year Mission Before Failure

The IRNSS-1F satellite was launched on March 10, 2016, and had recently completed its planned mission duration of 10 years. According to sources in the space department, the spacecraft’s last operational atomic clock malfunctioned, bringing an end to its navigation functionality.

The satellite had originally been equipped with three atomic clocks, but over time two had already stopped functioning. The final clock continued operating for some time before failing.

Officials from the Indian Space Research Organisation (ISRO) did not comment directly on the issue when approached for clarification. Instead, the agency pointed to a statement released on its website.

“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 its official statement issued on Friday night.

The agency also confirmed the satellite had reached the end of its planned life cycle.

“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.

Minimum Satellite Requirement for NavIC Services

The NavIC navigation system requires at least four operational satellites to provide reliable navigation services to users across India and surrounding regions.

These services support several critical sectors, including railways, transportation systems, disaster management operations, and military applications.

Following the reported failure of IRNSS-1F, the number of satellites providing Position, Navigation and Timing (PNT) services has dropped further.

At present, the satellites believed to be delivering PNT services include:

• IRNSS-1B
• IRNSS-1L
• IRNSS-1J (also known as NVS-01)

Sources within the space department said the failure could affect navigation services provided through NavIC.

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

Several NavIC Satellites Operating Below Full Capacity

India has launched 11 satellites for the NavIC system since July 2013 as part of a programme costing nearly ₹2,250 crore. However, the constellation has experienced multiple technical issues over the years.

Many of the satellites launched in the initial phase developed faults due to defective imported atomic clocks, while some others encountered orbital challenges after launch.

In July 2025, the Union government informed Parliament about the operational status of the NavIC satellites.

“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 Prime Minister’s Office Jitendra Singh said in a reply in the Lok Sabha on July 23, 2025.

With the failure of IRNSS-1F, the number of satellites providing full navigation services has now dropped even further.

Atomic Clock Failures Continue to Challenge NavIC

Atomic clocks play a critical role in satellite navigation systems. They allow satellites to keep extremely precise time, which is essential for calculating accurate positions on Earth.

Navigation systems determine a receiver’s position by measuring the time taken for signals to travel from satellites to ground-based receivers. Even tiny errors in these clocks can significantly distort location data.

In fact, a small deviation in the timing signal can shift position estimates by hundreds of kilometres.

Several NavIC satellites have already experienced atomic clock failures in the past. These include:

• IRNSS-1A (launched July 1, 2013)
• IRNSS-1C (October 16, 2014)
• IRNSS-1D (March 28, 2015)
• IRNSS-1E (January 20, 2016)
• IRNSS-1G (April 28, 2016)

With the failure of IRNSS-1F, six out of the 11 satellites deployed for NavIC have faced problems related to atomic clocks.

Origins of the NavIC Programme

The NavIC programme was initiated after the 1999 Kargil war, when Indian defence forces faced difficulties accessing the US-owned GPS system to obtain precise location data in the conflict zone.

The experience underscored the strategic need for India to develop its own satellite navigation capability.

As a result, ISRO began work on the IRNSS programme in 1999, eventually leading to the creation of NavIC, India’s independent regional navigation system designed to provide services across the country and nearby regions.

Efforts to Improve Satellite Clock Technology

After early atomic clock failures, ISRO acknowledged in July 2016 that the IRNSS-1A satellite had developed problems due to malfunctioning clocks. The agency indicated that replacement satellites would be launched with modified clock technology.

The original atomic clocks used in IRNSS satellites were supplied by a European manufacturer under a contract valued at approximately €4 million. The deal covered about 45 clocks, with each satellite carrying three clocks to ensure redundancy.

Later satellites launched after July 2016, such as IRNSS-1H and IRNSS-1I, were equipped with modified versions of the original clocks.

Second-Generation NavIC Satellites Introduced

India has also begun deploying second-generation navigation satellites under the NVS series.

Two of these satellites include:

• IRNSS-1J (NVS-01) – currently operational
• IRNSS-1K (NVS-02) – which reported an engine failure last year

These newer satellites incorporate a combination of indigenous and foreign atomic clocks in an effort to improve reliability.

Although the full NavIC constellation ideally requires seven satellites, experts say the system can still provide essential navigation services with fewer.

“To provide a solution for position navigation and timing, only four satellites are needed—for timing, only one satellite is sufficient, and for position navigation, four satellites are sufficient. So we do have an indigenous solution through the IRNSS constellation at present,” the spacecraft director for the NVS-02 mission, Kartik A, said on January 29, 2025.

Orbit Problems Affect Some Satellites

Not all NavIC satellite issues have been related to atomic clocks. Some spacecraft have faced challenges reaching or maintaining their intended orbit.

Two such satellites include:

• IRNSS-1H, launched on August 31, 2017
• IRNSS-1K (NVS-02), launched on January 29, 2025

ISRO’s statement regarding this says, “On separation of the satellite from the launch vehicle, a series of autonomous activities on the satellite were carried out including the solar panel deployment and stabilizing the orientation for power generation. However, the orbit raising operations from the elliptical to circular orbit could not be carried out,” the agency said.

The statement also outlined the probable cause of the malfunction.

“The apex committee after thorough analysis of the simulation data concluded that the prime reason for the observation was found to be the drive signal not reaching the pyro valve of the oxidizer line of the engine meant for orbit raising. The committee concluded that the most likely cause for the observation is the disengagement of at least one contact (in each of the main and redundant paths) of the connector,” the statement added.

Launch Failures Delay Future NavIC Expansion

The challenges facing the NavIC constellation have been compounded by setbacks in India’s launch programme.

ISRO recently experienced two consecutive launch failures involving its Polar Satellite Launch Vehicle (PSLV) during the 2025–26 period. In one case, the PSLV-C62 mission encountered technical problems.

“The PSLV-C62 mission encountered an anomaly during the end of the PS3 stage. A detailed analysis has been initiated,” ISRO said after the incident on January 12, 2026.

A national-level review committee was later formed to examine the issue. “A national level expert committee constituted is reviewing the reason for anomaly in PSLV Vehicle,” the agency said in another statement on February 25, 2026.

Future NavIC Satellites Planned

Despite the setbacks, India plans to strengthen the NavIC constellation by launching additional second-generation satellites.

Earlier, the government had informed Parliament that NVS-03, NVS-04, and NVS-05 would be launched sequentially, starting in late 2025 and continuing at six-month intervals. The hardline is this, that even after completing a quarter century of Kargil, the country is failed to established its own navigation system. And has to rely on Russian or American systems.

However, the launch schedule has been delayed following recent rocket failures.

ISRO has said the upcoming satellites will augment the NavIC base-layer constellation with enhanced features and help ensure the continuity of navigation services.

For a system created to guarantee India’s strategic independence in navigation technology, restoring the constellation’s strength and reliability remains a key priority for the country’s space programme.