When a Trusted Rocket Breaks—Inside the Failure That Stalled India’s Launch Machine
PSLV-C62 failed after a third-stage anomaly. What likely went wrong, how ISRO investigates launch failures, and what delays this means for India’s space programme.
PSLV-C62 failure: what likely went wrong, how investigations work, and what slips next
A rocket failure is rarely a single bad part. It is almost always a systems story: reliability margins, anomaly chains, and small things that line up at the wrong moment.
PSLV-C62 lifted off from Sriharikota carrying the EOS-N1 Earth-observation satellite along with multiple co-passenger payloads. ISRO later confirmed the mission encountered an anomaly during the end of the third stage, preventing the vehicle from reaching its intended orbit. A detailed investigation is now under way.
This piece explains what most likely failed, how ISRO investigations typically proceed, and what the knock-on consequences are for India’s launch schedule and partners.
What happened (minute-by-minute)
Two timelines matter: what was visible publicly, and what the planned flight sequence looked like.
Observed sequence
Lift-off occurred on schedule, with early ascent appearing nominal.
During the later portion of powered flight, telemetry and trajectory updates became irregular.
ISRO subsequently confirmed a disturbance and deviation during the end of the third stage (PS3).
Planned sequence (context for failure location)
Third-stage ignition occurs roughly four to five minutes after launch.
Third-stage separation normally follows around eight minutes into flight.
Fourth-stage ignition and orbit-insertion manoeuvres occur after that.
Payload separation was planned much later, once orbit was established.
Because the anomaly occurred at the end of PS3, the failure almost certainly happened before the vehicle was in a stable, recoverable orbital insertion phase.
What the third stage does
PSLV is a four-stage vehicle. Each stage hands the mission to the next:
The first two stages get the rocket out of the dense atmosphere and onto a high-energy climb.
The third stage provides a large velocity boost and stabilises the trajectory so the final stage can do precision orbital work.
The fourth stage fine-tunes the orbit and handles payload deployment.
If the third stage under-performs, over-performs, or destabilises the vehicle, the fourth stage never gets a usable starting condition. At that point, payload separation becomes irrelevant because the mission geometry is already lost.
What “anomaly” can mean
ISRO’s use of the word anomaly is deliberate. Until data is fully analysed, it avoids pinning blame on a single subsystem. In third-stage events, the realistic failure modes usually fall into a few categories:
Propulsion issues
Drop in chamber pressure
Incomplete or uneven propellant burn
Nozzle or insulation problems
Guidance and control instability
Unexpected roll or attitude divergence
Sensor faults feeding incorrect data to the guidance system
Control authority exceeded even though thrust continues
Structural or transition issues
Stage separation dynamics
Vibration or flex affecting control
Thermal or pressure stresses near burnout
Importantly, a “third-stage anomaly” does not automatically mean the motor exploded. Loss of controlled flight can be just as mission-ending.
Why payload loss matters
This was not a single-satellite mission.
Primary payload
EOS-N1, an Earth-observation satellite intended for strategic imaging and monitoring.
Secondary payloads
A mix of international, commercial, and academic spacecraft.
Technology demonstrators and small satellites from Indian and overseas partners.
The consequences are layered:
Strategic capability is delayed.
Commercial customers face rebuilds, re-testing, and re-booking launches.
Confidence in rideshare offerings takes a hit, particularly for international users.
How failure investigations actually proceed
Launch investigations follow a disciplined, methodical path:
Data lock-down
All telemetry, radar tracking, and ground-system logs are preserved.
Anomaly review board
Engineers identify the first deviation from nominal behaviour.
The initiating event is classified: propulsion, guidance, structural, or instrumentation.
Reconstruction and simulation
The flight is replayed using high-fidelity models with real sensor data.
Results are compared against nominal flights and ground tests.
Hardware and process traceability
Manufacturing records, inspection results, and configuration changes are reviewed.
Particular attention is paid to production lots and late-stage integration steps.
Corrective actions
Design, process, or inspection changes are defined.
Independent review is required before return-to-flight approval.
This process takes weeks to months depending on complexity.
The reliability record: what’s normal vs alarming
PSLV earned its reputation as a workhorse because failures were historically rare.
What raises concern now is pattern, not absolute numbers:
A third-stage-related failure occurred less than a year earlier.
PSLV-C62 again points to the same stage family.
One failure can be statistical noise. Two clustered failures in the same system force a deeper look at manufacturing controls, quality assurance drift, or latent design sensitivities.
Supply chain and quality-control pressure points
If PS3 is again central to the investigation, scrutiny will likely focus on:
Solid propellant casting and curing consistency
Nozzle and insulation bonding
Pressure measurement accuracy versus true chamber conditions
Vendor changes or component substitutions
Integration and handling processes late in the campaign
As launch cadence increases and commercial pressure grows, these “last-mile” risks become disproportionately important.
What missions and partners get delayed next
A PSLV stand-down is the default response until root cause is understood.
Likely consequences:
Rideshare payloads are reshuffled or moved to later missions.
Customers may seek alternative launch providers for time-critical spacecraft.
Internal schedules compress as testing, reviews, and corrective work overlap.
Even missions on different vehicles can feel indirect effects due to shared teams and infrastructure.
The reputational and insurance angle
Reputation
PSLV’s value proposition is reliability at moderate cost. Repeated anomalies challenge that perception and invite closer scrutiny from customers.
Insurance
After clustered failures, insurers often:
Increase premiums,
Tighten exclusions,
Demand more pre-flight evidence and reviews.
Those costs ultimately feed back into launch pricing and customer decisions.
What to watch for in the next 72 hours
The early signals that matter most:
Whether ISRO characterises the issue as propulsion-related or guidance-related.
Confirmation that no payload separation occurred.
Clarity on whether telemetry loss was a cause or a consequence.
Initial tone on return-to-flight timing: contained fix versus systemic review.
Those answers will determine whether PSLV-C62 is a painful but isolated event — or a trigger for deeper changes across the programme.
