Evaluate flight evidence and stage disposal

PSLV’s record includes useful services and unsuccessful flights. ISRO’s spacecraft list records EOS-09 on PSLV-C61 in May 2025 and EOS-N1 on PSLV-C62 in January 2026 as unsuccessful launches. The C62 mission page reports an anomaly near the end of the PS3 stage while also retaining earlier prelaunch text. The planned passenger sequence on that page is not evidence that it occurred.

An April 1, 2026 Department of Space reply described an expert review and return to flight after corrective actions. That is a dated account of the process, not proof of a subsequent successful launch. This lesson does not infer an undisclosed root cause or claim that two anomalies in the same stage must share one cause.

A useful investigation connects time-stamped telemetry, configuration records and physical models. Finding where a departure appears helps narrow the problem; it does not by itself identify the initiating defect. A proposed correction needs evidence that it addresses the mechanism and does not create another problem elsewhere.

In an original reliability exercise, a team reports 18 successes in 20 defined trials. The observed proportion is 90 percent. It is a description of those trials, not a guarantee that the next flight has precisely that success probability. Check what counts as success, whether trials share the same configuration and how a design change affects their relevance.

Separate claims from flight evidence

A final stage can continue as an experimental platform after releasing a satellite. For PSLV-C58 in January 2024, the stage became POEM-3; ISRO reports lowering its orbit from about 650 to 350 kilometres and removing residual propellant to reduce breakup risk. The stage reentered in March 2024. POEM supported experiments during this limited orbital lifetime.

Lowering an orbit exposes the stage to greater atmospheric drag, while passivation addresses stored-energy hazards. Those are different measures. Neither means the stage was recovered and reused as a launch vehicle. A responsible mission account distinguishes the active payload, the remaining rocket hardware, planned disposal and the observed end of the stage’s orbital life.