ISRO successfully tests Gaganyaan engine with new bootstrap mode
19 Nov 2025

The Indian Space Research Organisation (ISRO) has achieved a major milestone in its human spaceflight program.

The space agency successfully tested a new start-up method for the CE20 cryogenic engine, which will power the Gaganyaan mission on board the LVM3 launch vehicle.

The test was conducted at ISRO's Propulsion Complex in Mahendragiri on November 7, 2025.

ISRO's CE20 engine achieves bootstrap start
Engine success

The CE20 engine, which has already been flight-tested at thrust levels ranging from 19 to 22 tons, has now achieved a bootstrap start.

This is the first time a gas-generator cycle cryogenic engine has achieved this feat without an auxiliary stored-gas system.

The new method uses a multi-element igniter in both the thrust chamber and gas generator, eliminating the need for stored gas to ignite and activate its turbopumps.

Bootstrap start enhances LVM3's capabilities
Mission flexibility

The bootstrap start method allows the turbopumps to spin up autonomously, making the engine ramp up smoothly to a stable operating state.

This innovation significantly enhances the capabilities of the LVM3 rocket by making it lighter and more efficient.

It also enables ISRO to perform multiple in-flight restarts with ease, which is critical for multi-orbit deployments, complex mission profiles, and human spaceflight requirements.

Bootstrap start method boosts Gaganyaan mission
Mission boost

The bootstrap start method is a timely boost for the Gaganyaan mission, which aims to send Indian astronauts into space aboard an Indian rocket for the first time.

With improved restart capability and greater operational flexibility, the CE20 engine's new mode strengthens ISRO's position in both scientific and commercial space sectors.

It also brings India closer to its historic first crewed launch.