CHENNAI: ISRO has successfully completed a series of Crew Module-Service Module (CM-SM) separation tests, marking a crucial step towards ensuring astronaut safety in India's first human spaceflight mission, Gaganyaan, the space agency announced on Friday.

The Gaganyaan mission aims to send a three-member crew to a low Earth orbit (LEO) at an altitude of about 400 km for three to seven days before bringing them safely back to Earth, with a sea splashdown in Indian waters.
According to ISRO, the Gaganyaan Orbital Module comprises the crew module (CM), which houses the astronauts, and the service module (SM), which supports the crew module during the mission. The two modules are connected through a separation system, while electrical and fluid services are maintained through umbilical connections.

The modules remain integrated from launch until the completion of the orbital phase. Before the spacecraft re-enters Earth's atmosphere, the crew module must separate from the service module through a series of precisely sequenced operations involving pyrotechnic devices and jettisoning systems.

To validate the overall design and reliability of the separation system, ISRO established a test setup at the Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram. The setup simulated the integrated CM-SM assembly and was equipped with extensive instrumentation to assess the separation process, including the severing of multiple umbilical connections between the modules.

The tests also demonstrated the robustness and shock survivability of several critical crew module subsystems, including avionics systems, inertial navigation systems, the thermal protection system in the aft and conical heat shields, and the deployable umbilical shield.

In addition, the tests assessed the ability of pyrotechnic devices associated with the Crew Module Uprighting System and the Thermal and Humidity Control System to withstand the separation sequence.

The successful completion of the tests provides confidence in the performance of the CM-SM separation system ahead of the first uncrewed Gaganyaan mission, which ISRO is targeting for launch by the end of 2026.