On February 7, 2025, ISRO successfully conducted an ignition experiment of the indigenous CE20 cryogenic engine powering the upper stage of LVM3, using a Multi-element igniter under vacuum conditions, simulating engine ignition in space. This test was carried out at the ISRO Propulsion Complex’s High Altitude Test Facility in Mahendragiri, Tamil Nadu.
During this test, the engine Thrust Chamber was ignited in vacuum using a multi-element igniter at tank pressure circumstances similar to those predicted for restarting the cryogenic engine in flight. The engine and facility performed normally and predictably during the test.
Restarting a cryogenic engine is inherently complicated, and as part of its restart operation research, ISRO is investigating the startup of turbopumps in bootstrap mode rather than the stored gas system. Both the thrust chamber and the gas generator are intended to re-ignite under tank head circumstances. ISRO has proposed a series of tests aiming at engine starts in bootstrap mode to improve the capacity for multiple cryogenic engine restarts during flight.
Previously, the engine igniting trial with a multi-element igniter was conducted outside the vacuum chamber on the ground. The engine is already qualified to operate at thrust levels ranging from 19t to 22t in flight with a single start and is suitable for the Gaganyaan mission. The engine was developed by ISRO’s Liquid Propulsion Systems Centre.
