ISRO conducts flight acceptance test of CE20 cryogenic engine for LVM3-M6 mission

New Delhi: The Indian Space Research Organisation (ISRO) has successfully conducted the flight acceptance hot testing of the cryogenic engine for the LVM-M6 mission, the space agency said.

The hot testing is part of acceptance for the flight of Cryogenic engines for every mission.

“On March 14, 2025, ISRO successfully conducted the flight acceptance hot testing of the cryogenic engine identified for the sixth operational mission of LVM3 launch vehicle (LVM-M6) at ISRO Propulsion Complex (IPRC), Mahendragiri,” the space agency said.

Notably, hot tests for the indigenous cryogenic engine (CE20) used in the Cryogenic Upper Stage of LVM3 were so far performed at the High-Altitude Test (HAT) facility at IPRC. At IPRC, vacuum conditions are simulated with complex installations, limiting the maximum hot test duration to 25s.

However, in the new test, the engine was tested for a longer duration of 100s for the first time using an innovative Nozzle Protection System under non-vacuum conditions.

“This test method significantly reduces the setup time and effort required for the flight acceptance testing of a cryogenic engine, which in turn helps faster delivery of cryogenic stages for space missions,” ISRO said.

“Performance of the CE20 engine met all the test objectives and the parameters were closely matching with the predictions during the entire duration of the test,” it added.

Further, the space agency aims to integrate the engine into the Cryogenic Upper Stage of the launch vehicle for the LVM3-M6 mission — scheduled during the second half of 2025.

ISRO Chairman Dr V Narayanan said that Indian scientists aced the cryogenic technology on their own with an extreme level of dedication, after being denied by multiple countries.

“A major achievement is that we have developed the C 32 cryogenic propulsion system, and all should know that cryogenic technology was denied to India by other countries, and we took baby steps. Today, we have developed three cryogenic stages,” said Narayanan, while speaking to reporters.

“We have successfully tested it for 100 seconds. This is yet another technology that so many countries do not have. Even 20 years ago, it was a very hard technology, but today, it is for ISRO,” he added.

Meanwhile, ISRO confirmed the successful undocking of the Space Docking Experiment (SpaDeX) mission. With this, India has joined an elite group of four nations that have successfully demonstrated the complex technology of satellite docking and undocking, Narayanan said.

Recalling the preparations the organisation did before the mission, Narayanan mentioned that they carried out over 120 computer simulations of the mission to make sure there wouldn’t be any mistakes during the mission.

The SpaDeX mission lifted off aboard the PSLV-C60 rocket, from Sriharikota on December 30.

On January 16, the two satellites — SDX-01 (Chaser) and SDX-02 (Target) — were successfully docked together, demonstrating ISRO’s space docking ability.

“It was rotating as a single body. Then, we wanted to separate it, the undocking process, for that we carried out a lot of studies and analysis and we made a simulator and carried out 120 simulations, as there should not be any mistakes. On 13th March, at 9:20 am, in the first attempt itself, we succeeded in the undocking process,” the ISRO chairman said.

The undocking process included the successful extension of SDX-2, the planned release of Capture Lever 3, and the disengagement of the Capture Lever in SDX-2.

After these maneouvers, the decapture command was issued in both SDX-1 and SDX-2, leading to the successful separation of the satellites, ISRO said.

IANS