ISRO clears major milestone for Gaganyaan mission: What the successful propulsion test means for India’s first crewed space mission

This milestone leads India a step further to actually placing its astronauts into orbit

The Indian Space Research Organisation (Isro) has successfully completed the development and qualification testing of the Service Module Propulsion System (SMPS) for its ambitious Gaganyaan mission-India’s first human spaceflight programme. This milestone leads India a step further to actually placing its astronauts into orbit, Shubhanshu Shukla being one among those whose names are slated for Gaganyaan in the years to come.

Isro on Friday conducted a 350-second hot test at its Propulsion Complex in Mahendragiri, Tamil Nadu, simulating an off-nominal flight scenario—specifically, an abort condition during ascent. The test proved that the propulsion system succeeds in performing its intended functions even during emergencies.

The SMPS acts as the main propulsion system for the Gaganyaan Service Module to carry out operations such as orbital adjustments, in-space manoeuvres, re-entry de-boosting, and emergency crew escape.

The system boasts five Liquid Apogee Motor engines and 16 RCS thrusters, which are very precise in terms of attitude control, being required in both nominal and emergency flight conditions.

With this distinction, isro has demonstrated that the SMPS is flight-worthy and can withstand expected situations as well as off-nominal conditions. This is even more important for human-rated missions, where the safety of the crew must be paramount.

Isro subjected the System Demonstration Model to a series of 25 rigorous tests across various scenarios, culminating in a firing time of about 14,331 seconds, inclusive of both nominal and off-nominal manoeuvres.

The successful qualification verifies the reliability and robustness of the propulsion system, the critical factors needed to satisfy the human-rating objectives.

The propulsion system developed by LPSC in its entirety is now looked at as the human-rated historic system, which means that it conforms to strict safety and reliability requirements necessary for crewed missions.

With the SMPS now qualified, Isro is working toward integrating the Gaganyaan spacecraft and furthering associated elements, including the human-rated LVM3 rocket, the Crew Escape System, and the forthcoming uncrewed test missions.

India’s Gaganyaan mission, upon launch, will position the country as the fourth in the world—after the US, Russia, and China—to send humans into space using fully indigenous technology.

The recent propulsion system test isn’t just a routine achievement; it’s a vital validation that the spacecraft is capable of safely transporting astronauts through the extreme conditions of space.

As global focus sharpens on India’s growing space ambitions, this success underscores Isro’s commitment to advancing human spaceflight and laying the groundwork for future long-duration missions, including potential lunar expeditions.