ISRO's Successful LVM-3 Cryogenic Engine Test: A Major Milestone

The Indian Space Research Organisation (ISRO) has successfully conducted the ignition trial of the indigenous CE20 cryogenic engine, designed to power the upper stage of its powerful Launch Vehicle Mark-III (LVM-III).

The ignition of the engine Thrust Chamber was carried out with a multi-element igniter in a vacuum. (Photo: Isro)

During the test, ISRO engineers ignited the engine under vacuum conditions, simulating the environment it will encounter in space after the first two stages shut down and separate.

The trial was conducted at the High Altitude Test Facility of the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu.

Why is this ISRO test significant?

The engine's Thrust Chamber ignition during the test was achieved using a multi-element igniter in a vacuum, simulating the tank pressure conditions anticipated during the cryogenic engine's in-flight restart.

Cryogenic engines are intricate systems that utilize supercooled fuels, such as liquid hydrogen and oxygen. By successfully igniting the engine in a vacuum, ISRO showcases its increasing expertise in advanced propulsion systems, positioning itself alongside leading space agencies like NASA, ESA, and Roscosmos.

"We want to restart the cryogenic stage in the flight for mission advantages. So, we recently carried out a test towards that," ISRO chief V Narayanan said.

ISRO is testing the "bootstrap mode" ignition, where the engine restarts using pressure from its own fuel tanks rather than relying on a stored gas system. If successful, this method will enhance the efficiency and reliability of cryogenic restarts while reducing dependence on additional hardware.

This ignition technology will facilitate the deployment of satellites in multiple orbits, support complex interplanetary missions requiring trajectory corrections, and improve efficiency in human spaceflight programs like Gaganyaan.

The human-rated version of the LVM-III rocket, which will be used for the Gaganyaan mission, requires in-orbit ignition.

Speaking as the chief guest at the Aero India International Seminar 2025, Narayanan addressed concerns about project delays, emphasizing that ISRO and the aerospace sector handle highly complex and challenging missions.

He highlighted how, despite being denied access to cryogenic technology, ISRO successfully designed and developed the C25 Cryogenic Propulsion System for the GSLV Mk-III launch vehicle.

(This Article was originally published by India Today)