BENGALURU: Isro has successfully completed the development of the Service Module Propulsion System (SMPS) for the Gaganyaan human spaceflight mission, marking a milestone in the programme’s progress. The qualification test programme concluded with a full-duration hot test of the SMPS that lasted 350 seconds. “The test, conducted on July 11, validated the propulsion system’s integrated performance for an off-nominal mission profile involving a service module-based mission abort. The system performed normally, as predicted,” Isro said.The service module of Gaganyaan is a regulated bi-propellant propulsion system. It enables orbit circularisation, on-orbit control, de-boost manoeuvres, and provides abort capability during ascent. “The main propulsive force comes from the Liquid Apogee Motor (LAM) engines, while Reaction Control System (RCS) thrusters ensure accurate attitude control,” Isro said.To support testing, Isro developed a System Demonstration Model (SDM) replicating the fluid circuit of the SMPS, including propellant feed, helium pressurisation, flight-qualified thrusters, and control components. This testbed underwent 25 tests under both normal and off-nominal conditions, totalling 14,331 seconds, to meet various mission and human-rating requirements.The SMPS was developed by the Liquid Propulsion Systems Centre (LPSC), and all tests were carried out at the Isro Propulsion Complex in Mahendragiri.