Nellol: ISRO’s Polar Satellite Launch Vehicle (PSLV) is regarded as the main force in reliability and combat worldwide. However, the failure of the PSLV-C61 – after a sudden chamber pressure drop in its third phase of solid rocket motor, had a striking impact on space scientists.
Space flight is inherently complex, a senior scientist said Monday.
Despite this mission being lost, the activity provides crucial insights into the complexity of solid advancement and the scientific spirit of emphasis on ISRO’s resilience. Solid rocket motors (such as those in PSLVs) are valued for their simplicity and thrust efficiency.
However, they demand absolute internal integrity. Once ignited, these motors cannot be restricted or turned off. As shown in the third stage of PSLV-C61, sudden buck in combustion usually indicates an abnormality in the moving assembly.
“The chamber pressure in the third phase dropped sharply after nominal start, a signature pointing to structural or thermal protection failures. We are carefully studying the behavior of nozzle materials, grain bonding quality, insulation properties and casing strength.”
This is a setback, but it is also an important opportunity to increase profit margins in our system. ”
Globally, similar failures have occurred even in mature plans. The Zefiro 40 motor from the European Vega-C failed in 2022 due to shell erosion. NASA’s Titan 34D-9 and Titan IV-K11 rockets suffered from solid motion abnormalities in the 1980s and 1990s, related to grain defects and insulation vulnerabilities.
This situation usually stems from minor defects that rapidly escalate under high pressure combustion. One of the most common causes of pressure loss is grain cracks or voids, insulating combustion, propellant division and delamination, nozzle failure and flame instability, which can be locally quenched.
Even secondary defects can greatly alter the internal flow dynamics, resulting in pressure collapse or structural failure within milliseconds.
Despite the failure, the legacy of PSLV remains intact. With over fifty years of experience, ISRO repeatedly demonstrates an institutional culture of learning from adversity. For example, Chandrayaan-2 Lander’s 2019 anomalies informed the design changes, giving Chandrayaan-3 an accurate landing.
The failure of the PSLV-C61 is expected to lead to grain casting, bonding inspection, material testing, and controls that may integrate other sensors for early abnormality detection.
“A failure like this, when rigorously analyzed, tell us that it occurs in more than a dozen normal flights. Solid propulsion is a mature field, but not without risks. Every data point can help us evolve. PSLV is a proven vehicle – it will recover to be powerful.”
As Isro advances through ambitious projects such as Gaganyaan and reusable launch systems, its ability to mine insights from failures remains a decisive strength. Scientists assert that indoor pressure may have fallen in the third phase of PSLV-C61 – but the ISRO spirit based on discipline and determination is still firmly maintained in course.
