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.

The crew module of Gaganyaan has got a bipropellant-based Propulsion System for providing 3-axis control (Pitch, Yaw & Roll) to Crew Module following Service Module separation during re-entry i.e from an altitude of 170 km to 7 km till the deployment of the parachute-based deceleration system. It also provides attitude control in the ascent phase abort, if any, from 3 km to 70 km.

The crew module propulsion system hardware consists of 12 nos. of 100 N thrusters and associated flow control components. On April 5, 2023, the hot test of the Crew Module Propulsion System for demonstrating the nominal re-entry for the duration of 650 s was successfully conducted at ISRO Propulsion Complex, Mahendragiri. Prior to this, a series of tests were carried out with six nos. of Thrusters.

This system was designed, developed, and realized by Liquid Propulsion Systems Centre, Valiamala. Completing this test is a major step in qualifying the Crew Module Propulsion System for the Gaganyaan Program.