ISRO's Groundbreaking Engine Test for LVM-3 Rocket
In a significant advancement for India's space capabilities, the Indian Space Research Organisation has successfully conducted a crucial test that promises to enhance the flexibility of its flagship LVM-3 rocket. The space agency announced Wednesday that engineers have demonstrated a boot-strap mode start of the CE20 cryogenic engine under vacuum conditions for the first time.
The Revolutionary Test Details
The historic test was conducted on November 7, 2025, at the Isro Propulsion Complex in Mahendragiri. Engineers operated the engine for 10 seconds in the High-Altitude Test facility, simulating the vacuum conditions of space. This achievement marks a pivotal moment in India's cryogenic engine technology development.
The CE20 engine, which powers the upper stage of the LVM-3 rocket, had already been certified to operate at thrust levels between 19 and 22 tonnes with single ignition during flight. It has also received clearance for the prestigious Gaganyaan human spaceflight program. However, the conventional operation method presented limitations for future ambitious missions.
Overcoming Technical Limitations
Under normal circumstances, engine ignition begins under tank head pressure, followed by turbopump activation using a stored-gas start-up system. While effective, this approach becomes problematic for missions requiring multiple engine restarts in orbit. The existing configuration demands a separate gas bottle and associated systems for each restart attempt, significantly reducing the rocket's payload capacity.
ISRO engineers have been diligently working on the boot-strap mode starting technique as an innovative solution. This method enables the engine to reach stable operation without relying on external start-up assistance, thereby eliminating the need for multiple gas storage systems.
Technical Breakthrough and Future Implications
For this landmark test, ISRO implemented a multi-element igniter in both the thrust chamber and the gas generator. The process began with thrust chamber ignition, followed by lighting the gas generator under tank head conditions. Remarkably, the turbopumps were spun up without utilizing the conventional stored-gas system, with the engine successfully building up to steady operation in boot-strap mode.
This achievement likely represents the first instance globally where a gas-generator cycle cryogenic engine has accomplished such a start without auxiliary support. The milestone holds tremendous significance for future LVM-3 missions that will require complex orbital maneuvers, including multi-orbit deployments of satellites.
The successful demonstration of boot-strap mode starting opens new possibilities for India's space exploration ambitions. It enhances the LVM-3's capability to undertake more sophisticated missions while maintaining optimal payload capacity, positioning ISRO competitively in the global space industry.
