Why ISRO’s PSLV-C62 fell short: Ex-scientists explain what likely went wrong in crucial third stage

The mission to place the satellites in the intended orbit could not be achieved, and all 16 satellites were lost in space

• PSLV-C62 failed to place satellites in orbit due to third stage anomaly
• ISRO investigating the cause; satellites likely burned up on re-entry
• This marks the second consecutive PSLV mission with third stage issues

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A former ISRO scientist has shed light on what may have gone wrong during the PSLV-C62 launch, following the mission's failure to place its satellites into the intended orbit. Writing in India Today, the former ISRO scientist explained that while the first two stages of the rocket performed flawlessly, trouble emerged toward the end of the third stage — a critical solid-fuel motor that provides the final push needed to achieve orbit.

For the first few minutes, the launch appeared textbook-perfect, raising hopes of yet another successful Indian space mission. However, near the end of the third stage, ISRO detected a sudden disturbance. The rocket began twisting or rolling unexpectedly, causing it to deviate from its planned flight path.

Achieving orbit requires a precise balance of speed and direction. Objects in orbit must move fast enough to keep “falling around” the Earth rather than falling back to it. For instance, the International Space Station, orbiting at about 400 km altitude, travels at roughly 7.6–7.7 km per second (around 27,500–28,000 kmph), completing nearly 16 orbits a day.

In the PSLV-C62 mission, this exact combination of speed and stability was not achieved. The anomaly meant the rocket fell short of the required orbital velocity, preventing the upper stage and satellites from staying in orbit. Instead, their trajectory curved back toward Earth.

By the evening of January 12, 2026 — just hours after launch — the upper stage and any attached payloads were likely to have re-entered the denser layers of the atmosphere. Intense friction would have heated them to extreme temperatures, causing them to burn up like bright shooting stars. Any surviving fragments are believed to have fallen harmlessly into the ocean.

This marks the second PSLV mission in a row to face issues linked to the third stage, following a similar failure in PSLV-C61 in 2025. ISRO has constituted a dedicated team to analyse flight data, sensor readings and camera footage to pinpoint the root cause, which could range from uneven thrust and nozzle deformation to pressure issues during shutdown.

Another former senior ISRO scientist said it would take time for the agency to understand what went wrong fully. “It is expected that ISRO will officially release the findings in the days to come,” he told PTI on condition of anonymity.

Responding to a query, he added, “It is a setback as the satellites did not reach the intended orbit and all satellites lost in space maybe drifting as space debris.”

The 44.4-metre-tall, four-stage PSLV lifted off at 10.18 am after a 22.5-hour countdown from the spaceport, with the mission aimed at placing an Earth observation satellite and multiple co-passenger satellites into a 512-km Sun-Synchronous Orbit within about 17 minutes of flight.

ISRO scientists provided live updates as the vehicle climbed smoothly through the early phases. But after the announcement that the “third stage ignited”, tension spread inside Mission Control.

Addressing scientists later, ISRO Chairman S Somanath said, “The PSLV is a four-stage vehicle with two solid stages and two liquid stages. The performance of the vehicle up to the end of the third stage was expected. Close to the end of the third stage, we are seeing more disturbance in the vehicle, and subsequently, there was a deviation observed in the flight path.”

Confirming the anomaly on X, ISRO stated, “The PSLV-C62 mission encountered an anomaly during the end of PS3 (third stage) of the vehicle. A detailed analysis has been initiated.” However, the agency stopped short of officially terming the mission a failure.

In a brief press conference, Somanath said, “As all of you are aware, today we attempted PSLV-C62/EOS-N1 mission… the mission could not proceed in the expected (flight) path. That is the information right now available.” He added, “We are going through the data and with the data collected from all the ground stations, and once the data analysis is completed, we shall come back to you.”