ISRO's strategic satellite delays expose cracks in India's space readiness

The suspense continues over why India has not moved to strengthen its strategic satellite constellation despite having at least one navigation satellite ready for launch. Is the delay linked to the string of failures involving India's strategic space missions? That is the question increasingly being asked within the country's space community.

Curiously, two strategic satellites — navigation satellite NVS-03 and the multi-spectral and hyperspectral imaging satellite GISAT-1A — are reportedly ready and waiting at the Satish Dhawan Space Centre in Sriharikota for their launch vehicle. Both spacecraft are slated to be launched aboard the Indian Space Research Organisation's (ISRO) Geosynchronous Satellite Launch Vehicle Mk II (GSLV Mk II).

For several months, Dr V Narayanan, Secretary of the Department of Space and ISRO Chairman, has repeatedly said that India would soon launch its satellites. But when those launches will actually take place remains unanswered.

The delay assumes greater significance because India's regional navigation system, NavIC (Navigation with Indian Constellation), is today operating in a fragile state, with only three satellites fully capable of providing navigation services.

Puzzled over delay

Space industry experts told The Federal that India should even consider launching strategic satellites aboard rockets of friendly foreign space agencies if its own launch vehicles are unavailable, rather than allowing critical capabilities to deteriorate further.

Retired ISRO officials, meanwhile, are puzzled over the prolonged delay, particularly against the backdrop of repeated failures involving strategic missions. Questions are being raised within the space community.

Is ISRO being unusually cautious after successive failures? Why is it taking a long time to resolve any hardware issues flagged by the expert committee that looked into the recent mission failures? Are there unresolved issues involving launch vehicles, satellites, vendors, user segments, or even launch infrastructure? So far, there are no official answers.

NavIC hanging by a thread

India's satellite navigation constellation, NavIC, is effectively hanging by a thread. Of the eleven navigation satellites launched so far, only three — IRNSS-1B, IRNSS-1I, and NVS-01 — are presently capable of providing Position, Navigation, and Timing (PNT) services. Even these satellites do not always provide uninterrupted service.

The constellation is also ageing rapidly.

IRNSS-1B, launched in 2014, has already exceeded its planned ten-year mission life, while IRNSS-1I, launched in 2018, is approaching the same milestone. On March 13, 2026, ISRO announced that IRNSS-1F had completed its mission life after its onboard atomic clock failed. The satellite continues only limited messaging services.

Also Read: Why are top scientists quitting ISRO?

Given the prevailing geopolitical environment and growing national security concerns, experts believe India must urgently adopt a multi-pronged strategy to restore NavIC's reliability.

A recent report of the Department-related Parliamentary Standing Committee on Science and Technology, Environment, Forests and Climate Change suggests that even partial replenishment of the constellation may still take another 15-18 months.

The committee, in its report on the Demands for Grants for 2026-27 presented to Parliament on March 25, 2026, stated: "The replacement satellites NVS-03, NVS-04, and NVS-05 will be launched over the next 15-18 months."

A string of mission failures

India's strategic space programme has suffered a series of setbacks involving both launch vehicles and satellites. Several navigation satellites have already lost full capability because of failures of imported atomic clocks.

Many within the space sector trace the beginning of this difficult phase to the failure of the GISAT-1 mission in August 2021. The 2,268-kg GISAT-1 satellite was lost after the GSLV Mk II experienced a malfunction in its cryogenic upper stage. The three-stage rocket had already suffered two launch postponements because of technical glitches before finally lifting off.

ISRO's Failure Analysis Committee concluded that leakage through the Vent and Relief Valve resulted in abnormally low liquid hydrogen tank pressure during ignition of the cryogenic stage. The resulting malfunction of the Fuel Booster Turbo Pump eventually led to mission failure.

Following that setback, ISRO successfully used the GSLV Mk II to launch NVS-01, NVS-02, INSAT-3DS, and the Indo-US NISAR satellite.

Off intended orbit

The next setback came with the launch of NVS-02. Launched on January 29, 2025, during what was celebrated as the 100th rocket launch from Sriharikota, the Rs 300-crore navigation satellite was successfully injected into Geosynchronous Transfer Orbit by another Rs 300-crore GSLV Mk II.

However, the satellite failed to reach its designated geostationary orbit because the oxidiser valves required for orbit-raising operations failed to open. ISRO acknowledged the problem, but never explained why the valves failed.

Satellite experts believe the problem may have originated in the electrical connector supplying power to the oxidiser valve.

Also Read: Centre changes ISRO resignation rules amid exodus of experienced scientists

Ordinarily, mission-critical systems on launch vehicles and satellites are designed with complete redundancy. Officials familiar with satellite systems had earlier told this writer that the valves, electronics, and power systems all possessed redundant backups.

For crewed missions, critical systems generally incorporate three or four levels of redundancy.

Equally important, redundant systems should remain completely independent and not converge through a common failure point. Industry experts say critical components should also be sourced from different vendors to minimise batch-related risks.

If these principles were followed, what prevented power from reaching the oxidiser valve?

A retired senior ISRO official said that both the primary and redundant power supplies might have passed through the same connector, effectively defeating the objective of complete redundancy.

Even more disturbing for India's space establishment were the back-to-back failures of two PSLV missions carrying strategically-important satellites.

On May 18, 2025, PSLV-C61 failed about six minutes after lift-off, resulting in the loss of the EOS-09 (RISAT-1B) surveillance satellite and the launch vehicle. The combined loss was estimated at around Rs 850 crore.

EOS-09 carried a Synthetic Aperture Radar capable of all-weather surveillance and was intended to significantly strengthen India's strategic observation capability.

A retired senior ISRO official suggested the PSLV-C61 failure may have originated from a faulty valve or electrical connector that resulted in loss of pressure during third-stage operation.

Also Read: ISRO’s PSLV failure: Who pays when rocket missions go wrong?

Less than eight months later, on January 12, 2026, PSLV-C62 also failed. The rocket was carrying Anvesha (EOS-N1), DRDO's latest hyperspectral reconnaissance satellite, along with fifteen smaller Indian and foreign satellites. Anvesha was equipped with advanced hyperspectral sensors capable of identifying objects and materials invisible to conventional optical systems.

Dr Narayanan said the rocket developed a disturbance towards the end of third-stage performance, causing deviation from its intended flight path.

A rocket expert familiar with PSLV missions told this writer that the failure appeared strikingly similar to PSLV-C61.

"There is simply too much coincidence in back-to-back failures involving missions critical to national security," remarked a retired senior ISRO official.

Following the PSLV-C62 failure, the Government of India constituted a high-level committee headed by former Principal Scientific Adviser K Vijayraghavan, with former ISRO chairman S Somanath serving as co-chairman.

The move came after National Security Adviser Ajit Doval quietly visited the Vikram Sarabhai Space Centre in Thiruvananthapuram.

Although the Failure Analysis Committees investigating PSLV-C61 and PSLV-C62 have reportedly submitted their reports, they have not been released publicly, unlike previous ISRO failure reports.

Also Read: ISRO to triple spacecraft output, target Chandrayaan-4 launch in 2028: Narayanan

That departure from past practice has raised fresh questions within the space community.

Officials told The Federal that discussions relating to PSLV-related corrective measures are now being conducted strictly on a "need-to-know" basis. The repeated failures are worrying, not merely because of their financial implications but because they directly affect India's strategic capabilities.

Mission Drishti was intended to support defence, agriculture, disaster management, maritime surveillance, and infrastructure monitoring.

Also Read: ISRO plans to send astronauts to Moon by 2040

After remaining silent for over two months following launch, the company disclosed that the spacecraft had encountered an anomaly during the Launch and Early Orbit Phase. Initial analysis indicated that radiation generated by a geomagnetic solar storm likely damaged a critical onboard system, leaving only remote chances of recovering the satellite.

Earlier setbacks include the 2017 failure in which an Indian navigation satellite remained trapped inside the PSLV payload fairing after the separation mechanism failed to operate, and the maiden SSLV mission in 2022, which also failed to place its satellites into the intended orbit.

With strategic satellites already available, India should not indefinitely wait for domestic launch vehicles if they are not immediately ready.

Friendly foreign launch providers could be considered for deploying strategic, commercial, and societal satellites until domestic launch schedules stabilise.

At the same time, India should ensure that its critical satellite constellations maintain significantly more than the minimum number of operational spacecraft, backed by robust ground infrastructure and reserve capacity.

For a country increasingly dependent on space-based assets for national security, navigation, and surveillance, strategic resilience must take precedence over institutional inertia.