Broken electrical circuit behind ISRO’s failed launch of NVS-02 in January 2025: Committee

What Happened

ISRO officially disclosed on February 25, 2026, the root cause of the NVS-02 navigation satellite failure that occurred after its launch on January 29, 2025.
An Apex Committee investigation concluded that disengaged contacts in both the primary and redundant electrical connector paths broke the circuit, preventing ignition of the satellite's onboard apogee motor — the engine required to raise the satellite from its transfer orbit to the intended geostationary orbit.
Specifically, a pyrotechnic valve (pyro valve), which is activated by a small explosive charge to release oxidizer into the propulsion engine, failed to open because the electrical command could not reach it through the broken circuit.
NVS-02 remains stranded in an elliptical geostationary transfer orbit (GTO) — ranging from approximately 287 km to 37,252 km altitude — and cannot fulfil its mission role.
ISRO has since implemented corrective measures to improve redundancy and quality checks in pyrotechnic systems for future missions.

Static Topic Bridges

NavIC, formerly known as IRNSS (Indian Regional Navigation Satellite System), is India's autonomous satellite-based positioning system, designed and operated by ISRO. It provides accurate real-time positioning and timing services over India and a region extending approximately 1,500 km beyond its borders — covering South Asia, parts of Central Asia, and the Indian Ocean region.

Conceived after the 1999 Kargil War, when the US refused India access to GPS data for military operations — highlighting the strategic vulnerability of dependence on foreign navigation systems
The system uses a constellation of 7 operational satellites in two types of orbits: 3 in Geostationary Orbit (GEO) and 4 in Geosynchronous Inclined Orbit (GSIO), all at approximately 36,000 km altitude
NavIC provides two services: Standard Positioning Service (SPS) for civilian users (5-20 metre accuracy) and Restricted Service (RS) for strategic/military users (encrypted, sub-metre accuracy)
By early 2025, NavIC faced a severe constellation crisis: five IRNSS satellites became fully defunct (atomic clock failures), leaving only 2-4 satellites operational — critically below the minimum 4 needed for reliable 3D positioning
NVS series (NVS-01, NVS-02, NVS-03, NVS-04, NVS-05) are second-generation NavIC satellites, featuring domestically designed rubidium atomic clocks (replacing imported clocks that failed on earlier satellites)

Connection to this news: NVS-02 was critical to restoring NavIC's operational capability. Its failure to reach geostationary orbit means the constellation remains in a degraded state, dependent on the few surviving first-generation satellites and NVS-01 (launched May 2023, operational).

Pyrotechnic Systems in Spacecraft — Function and Failure Mode

Pyrotechnic devices (pyro valves, pyro bolts, cable cutters) are single-use explosive-actuated mechanisms used widely in spacecraft for time-critical, one-shot operations — such as releasing propellant valves, separating stages, or deploying solar panels. They are used because they are highly reliable when functioning correctly, but their single-use nature means there is no second chance if they fail.

A pyrotechnic valve (pyro valve) uses a small explosive charge to shatter a seal or drive a piston, permanently opening or closing a propellant line — allowing fuel or oxidizer to flow to a thruster
Redundancy in pyro systems is standard practice: both primary and redundant firing paths are provided so that a single circuit failure does not cause mission loss
In NVS-02's case, both the primary AND redundant electrical connector paths were disengaged, suggesting a common-cause failure at the mechanical connector interface rather than independent random failures
This type of failure — where redundancy is defeated by a shared mechanical weakness — is a classic reliability engineering concern known as a "common mode failure"
Post-investigation corrective measures typically include: improved connector locking mechanisms, enhanced pre-launch electrical continuity checks, and ground simulation testing under launch vibration conditions

Connection to this news: The NVS-02 failure illustrates that spacecraft failures are often caused not by design flaws in the technology but by manufacturing, assembly, or quality assurance lapses — in this case, connectors that were not fully engaged. ISRO's transparency in disclosing the root cause a year after the mission is a positive step for institutional learning.

GSLV (Geosynchronous Satellite Launch Vehicle) — History and Role

The GSLV (Geosynchronous Satellite Launch Vehicle) is ISRO's medium-lift launch vehicle, designed to place communication and navigation satellites of 2,000-2,500 kg mass into geostationary transfer orbit. It uses a cryogenic upper stage — a technologically demanding capability that ISRO developed indigenously after being denied the technology by the US in the 1990s.

First launch: April 18, 2001; as of mid-2025, GSLV has made 18 launches with 12 successes, 4 failures, and 2 partial failures — a reliability record that improved significantly after the indigenous cryogenic engine (CE-7.5) became operational
GSLV Mk-II (used for NVS-02): Three-stage vehicle — solid strap-ons + liquid core + indigenous cryogenic upper stage; can place ~2,500 kg to GTO
GSLV Mk-III (LVM3): Larger, heavier-lift variant that placed Chandrayaan-2, OneWeb satellites, and Chandrayaan-3; distinct from Mk-II
The NVS-02 mission itself (GSLV-F15) was a launch success — the rocket performed correctly and delivered the satellite to the intended transfer orbit; the failure occurred onboard the satellite during orbit-raising
GSLV is used for NavIC and GSAT (communication satellites); PSLV handles lighter remote sensing and scientific payloads

Connection to this news: It is important to distinguish: the GSLV rocket did not fail in this mission — it delivered NVS-02 correctly to its transfer orbit. The failure was in the satellite's own propulsion system. This distinction matters for assessing ISRO's launch reliability vs. spacecraft system reliability.

India's Space Programme — Strategic and Economic Dimensions

India's space programme, managed by ISRO under the Department of Space (reporting directly to the Prime Minister), has evolved from a purely scientific endeavour to a strategic and commercial asset. Navigation infrastructure like NavIC has both civilian applications (transport, agriculture, disaster management) and defence applications (precision guidance, border surveillance).

ISRO established 1969; Department of Space established 1972; legal framework: Space Activities Act is pending (bill introduced 2017, not yet enacted); currently governed by executive orders
IN-SPACe (Indian National Space Promotion and Authorisation Centre) established 2020 — regulatory body for private sector space activities
New Space India Limited (NSIL) — commercial arm of ISRO for launch services and satellite manufacturing
NavIC civilian applications mandated by government: all mobile devices sold in India from 2023 must support NavIC L1 and L5 signals (BIS mandate); major smartphone brands (Apple, Samsung, Xiaomi, OnePlus) now NavIC-compatible
Strategic significance: During Kargil War (1999), the US selectively degraded GPS accuracy for non-US users — India's motivation for building NavIC was to eliminate this vulnerability
ISRO's planned response: NVS-03, NVS-04, and NVS-05 to be launched by end-2026 to complete the second-generation NavIC constellation

Connection to this news: The NVS-02 failure is not just a technical setback — it has strategic implications for India's navigation sovereignty. Until the NavIC constellation is fully restored, India's military and critical civilian systems that depend on NavIC must rely on a degraded constellation or supplement with foreign GPS signals.

Key Facts & Data

NVS-02 launch date: January 29, 2025 (aboard GSLV-F15 from Sriharikota)
Root cause disclosed: February 25, 2026 (13 months after launch)
Failure mechanism: Disengaged electrical connectors in both primary and redundant paths → broken circuit → pyro valve did not fire → orbit-raising engine did not ignite
Current orbit: Stranded in GTO (287 km × 37,252 km, 20.85° inclination) — instead of intended geostationary orbit (~36,000 km circular)
NavIC operational satellites (as of early 2026): Critically reduced from original 7 — only 2-4 functional (5 first-generation satellites defunct due to atomic clock failure)
NavIC coverage: India + 1,500 km surrounding region; standard accuracy: 5-20 metres (civilian), sub-metre (restricted/military)
GSLV launch record: 18 launches total; 12 successes, 4 failures, 2 partial failures
NavIC conceived post-Kargil War (1999); operational since 2018
BIS mandate: All smartphones sold in India from 2023 must support NavIC L1 and L5 signals
NVS-01 (launched May 2023): Operational, first second-generation NavIC satellite with indigenous rubidium atomic clock
Upcoming launches: NVS-03, NVS-04, NVS-05 targeted by end-2026