ISRO Propels Gaganyaan Mission Forward with Critical Hot Tests of Service Module Propulsion System

Indian Space Research Organization (ISRO) achieved great success by successfully conducting the first hot test of the System Demonstration Model (SDM)

Mahendragiri, Tamil Nadu – In a significant leap forward for India's ambitious Gaganyaan human spaceflight mission, the Indian Space Research Organisation (ISRO) has successfully conducted a series of crucial "hot tests" of the System Demonstration Model (SDM) of the Gaganyaan Service Module Propulsion System (SMPS). These rigorous tests, performed at the ISRO Propulsion Complex (IPRC) in Mahendragiri, Tamil Nadu, validate the robust performance of the system vital for future manned missions.

The Service Module (SM) is an essential component of the Gaganyaan orbital module, positioned beneath the crew module and remaining attached until re-entry. Its propulsion system is a unified bipropellant system, critical for various maneuvers in space. The SMPS is equipped with five 440 N engines and sixteen 100 N Reaction Control System (RCS) engines, designed to provide both primary thrust and precise attitude control.

The latest series of hot tests, following an initial successful run on July 19, 2023, saw two more critical tests carried out on July 26, 2023. The first hot test, spanning an impressive 723.6 seconds, focused on demonstrating Orbital Module injection and conducting a calibration burn of the 100 N thrusters and Liquid Apogee Motor (LAM) engines. This calibration was crucial to ensure the optimal functioning of all engines and to identify any non-operational units. ISRO confirmed that both the LAM engines and RCS Thrusters performed as expected, a testament to their design and engineering.

The subsequent hot test, lasting 350 seconds, aimed to demonstrate the circularization of the Orbital Module to achieve the final orbit. During this test, the LAM engines operated in a continuous mode, while the RCS Thrusters fired in pulse mode, meticulously mimicking the operational profile required for mission success. The thrusters were also operated in both continuous and pulse modes across these recent tests, showcasing their adaptability and readiness for diverse in-orbit scenarios.

The entire Gaganyaan Service Module Propulsion System has been meticulously designed and developed by the Liquid Propulsion System Centre (LPSC), with its facilities located in Bangalore and Valiamala, Thiruvananthapuram.

Looking ahead, ISRO has planned three more hot tests. These forthcoming trials are designed to further validate the propulsion system's capabilities, specifically demonstrating de-boosting requirements and evaluating its performance under off-nominal mission scenarios. This comprehensive testing regimen underscores ISRO's commitment to ensuring the highest levels of safety and reliability for India's groundbreaking human spaceflight endeavor.

The successful completion of these hot tests marks a significant stride in the development of the Gaganyaan mission, bringing India closer to sending its astronauts into space.