ISRO Successfully Conducts Ground Test of Improved SSLV Third Stage at Sriharikota

The Indian Space Research Organisation (ISRO) successfully conducted a ground test of an improved version of the third stage (SS3) of the Small Satellite Launch Vehicle (SSLV) on December 30, 2025, at the Solid Motor Static Test Facility of the Satish Dhawan Space Centre (SDSC-SHAR), Sriharikota. The SSLV is a three-stage all-solid launch vehicle developed by ISRO which is amenable to industrial production. The tested third stage features a carbon-epoxy composite motor case, which significantly reduces the mass of the stage and thereby improves the payload performance of SSLV by about 90 kg. The stage also incorporates an improved design for the igniter and nozzle system, making it more efficient and robust. Nozzle control is implemented through a fault-tolerant electro-mechanical actuation system with low-power control electronics. During the static firing, the motor was instrumented with around 233 measurement points to capture parameters such as pressure, thrust, temperature, vibration and control electronics/actuator behaviour. The test duration was 108 seconds, during which the stage delivered a velocity capability of up to 4 km/s. All measured parameters were observed close to predictions throughout the test, confirming the design integrity. With this successful static test firing, the improved SS3 motor is qualified for induction in flight missions. The upgrade supports ISROs expanded commercial small-satellite launch programme and aligns with the commissioning of new solid motor production facilities in 2025 to meet growing domestic and international demand for dedicated small satellite launches.