On August 28, 2021, ISRO successfully conducted the first hot test of the System Demonstration Model (SDM) of the Gaganyaan Service Module Propulsion System for a duration of 450 s at the test facility of ISRO Propulsion Complex (IPRC), Mahendragiri, Tamil Nadu. The system performance met the test objectives and there was a close match with the pre-test predictions. Further, a series of hot tests are planned to simulate various mission conditions as well as off-nominal conditions.

The Service Module is part of the Gaganyaan Orbital module and is located below the crew module and remains connected to it until re-entry. The Service Module (SM) Propulsion System consists of a unified bipropellant system consisting of 5 nos. of 440 N thrust engines and 16 nos. of 100 N Reaction Control system (RCS) thrusters with MON-3 and MMH as Oxidizer and Fuel respectively. The System Demonstration Model (SDM), consisting of 5 nos. of 440 N engines and 8 nos. of 100 N thrusters, was realized to qualify the propulsion system performance in ground. A new test facility is established at IPRC, Mahendragiri for testing the SDM.

System Demonstration Model (SDM)

System Demonstration Model (SDM) at test bed