Over a year on, Isro says panel traces NVS-02 failure to pyro valve signal loss

BENGALURU: More than a year after the setback to its navigation satellite programme, Isro on Wednesday released the findings of an apex committee that investigated why the NVS-02 spacecraft failed to reach its intended orbit on Jan 29, 2025.The committee, it said, traced the anomaly to a failure in the spacecraft’s pyro system. According to the findings, the drive signal did not reach the pyro valve in the oxidiser line of the engine meant for orbit-raising manoeuvres. As a result, the engine could not be fired to shift the satellite from its transfer orbit into its final circular orbit.The panel concluded that the most likely cause was the disengagement of at least one contact in each of the main and redundant connector paths.

Despite redundancy built into the system, the electrical command required to trigger the pyro valve did not get through.NVS-02 was launched on Jan 29, 2025, aboard GSLV-F15 and was injected into an elliptical transfer orbit with an apogee of 37,785 km and a perigee of 170 km, at an inclination of 20.8°. After the spacecraft separated from the launch vehicle, the satellite carried out a sequence of autonomous operations, including deployment of its solar panels and stabilisation of its orientation to ensure power generation.

However, the planned orbit-raising operations from the elliptical transfer orbit to the designated circular orbit could not be executed. Following the anomaly, Isro constituted an apex committee to review telemetry data and conduct detailed simulation studies. The Wednesday statement by Isro marks the first comprehensive public account of what went wrong.Isro said the committee has recommended a set of corrective measures to enhance redundancy and improve the reliability of pyro system operations in future missions.

These recommendations have already been implemented.“The updated systems were flown on the CMS-03 mission, launched on Nov 2, 2025, aboard LVM-3 M5. The pyro systems performed as intended, and the satellite was placed in its designated orbit,” Isro said. It added that the recommendations will be followed for all future missions, as applicable, to prevent recurrence of similar failures.Meanwhile, more than a month after its PSLV-C62 failed on Jan 12 this year, Isro has constituted a Failure Analysis Committee (FAC) chaired by former Principal Scientific Secretary (PSA) Prof K VijayRaghavan and co-chaired by former Isro chairman S Somanath. TOI had reported earlier this month that Isro was yet to set up the FAC and that the initial analysis was being done by an expert committee that was called the “data analysis committee” or DAC internally. The FAC was constituted after the DAC submitted its report, details of which have not been made public yet.