MAHENDRAGIRI, October 9 — The Indian Space Research Organisation (ISRO) on Friday successfully completed the final human-rated qualification testing of the C25 Cryogenic Upper Stage engine at the High Altitude Test Facility of the ISRO Propulsion Complex (IPRC) in Mahendragiri, Tamil Nadu, clearing a definitive technological hurdle ahead of the uncrewed Gaganyaan-1 (G1) mission.
During the qualification test, the C25 cryogenic engine—powered by a mixture of Liquid Oxygen (LOX) and Liquid Hydrogen (LH2)—fired continuously for 720 seconds under simulated high-altitude vacuum conditions, exceeding nominal flight operational duration by 25 percent. Telemetry verified optimal chamber pressures, turbine rotational speeds, and propellant flow integrity, satisfying all human-rating safety margins prescribed for manned spaceflight.
With the successful qualification of the C25 stage, all three propulsion stages of the Launch Vehicle Mark-3 (LVM3)—the S200 solid rocket boosters, the L110 Vikas liquid core stage, and the C25 cryogenic upper stage—have completed their respective human-rating qualification regimes. The upcoming G1 orbital demonstration will deploy the humanoid robot 'Vyommitra' into a 400-kilometer low Earth orbit to validate life-support and crew module recovery protocols.
Indigenous aerospace propulsion (cryogenic engine cycles), human-rating protocols for launch vehicles (LVM3-M4/Gaganyaan), the Crew Escape System (CES) and Test Vehicle demonstrations (TV-D1), and long-term space exploration roadmaps (Bharatiya Antariksh Station by 2035, Indian lunar landing by 2040) are primary study themes for UPSC Civil Services (GS-III: Science and Technology). Aspirants should track ISRO's astronaut training pipeline administered at the Astronaut Training Facility in Bengaluru.