ISRO clears critical Gaganyaan separation test ahead of first uncrewed mission

The Indian Space Research Organisation (ISRO) has completed a series of tests on the system that will separate the crew capsule from its service module during the Gaganyaan missions. The tests come ahead of G1, the first uncrewed flight of India's human spaceflight programme, which the space agency has targeted for launch this year.

The Gaganyaan Orbital Module consists of two parts: the Crew Module (CM), which is designed to carry astronauts, and the Service Module (SM), which provides propulsion and other support functions. The two are joined by a separation system. Electrical and fluid servicing between them is maintained through umbilical connections. The modules are integrated before launch and function as a single unit from lift-off until the on-orbit phase of the mission is completed.

Before the crew module begins its re-entry into the earth's atmosphere, it must separate from the service module. This separation involves multiple precisely sequenced events that rely on pyrotechnic devices and jettisoning systems.

To validate the overall design adequacy of the separation system, ISRO set up a test arrangement at the Vikram Sarabhai Space Centre in Thiruvananthapuram, where the complete CM-SM assembly was simulated with extensive instrumentation.

The tests replicated the conditions of a CM-SM separation, including the severing of several umbilical connections between the two modules. ISRO said that besides validating the design adequacy of the overall separation systems, the tests demonstrated the robustness and shock-survivability of several critical subsystems within the crew module.

These subsystems include various avionics systems, inertial navigation systems, the thermal protection system in the aft and conical heat shield, the crew module deployable umbilical shield, and the pyrotechnic devices of the crew module uprighting system and the thermal and humidity control system.

ISRO said the exercise provides the necessary confidence in the functioning of the implemented CM-SM separation system for the upcoming G1 mission. Separation of the two modules is a safety-critical step: the crew module must detach cleanly and in the correct sequence for re-entry, parachute deployment and splashdown to proceed as planned.

The Gaganyaan programme envisages demonstrating human spaceflight capability by launching a crew of three members to an orbit of 400 km for a three-day mission and bringing them back safely to earth, with a landing in Indian sea waters. ISRO has said uncrewed missions will fly before astronauts are aboard, and G1 is the first of these preparatory flights. The agency has been conducting a range of ground tests on the crew module, parachute systems and other elements in the run-up to that mission.

The latest separation tests add to a growing body of ground validation for the programme. However, ISRO has not announced a specific date for the G1 launch, and schedules for space missions are subject to review following test results and hardware readiness.