One step closer to a bigger, stronger LVM3: Isro tests new engine at near-full thrust

India's space agency, Indian Space Research Organisation (Isro), has taken another important step toward building a more powerful version of its heaviest rocket, the LVM3.

On June 24, 2026, it successfully test-fired a key part of a new rocket engine at its propulsion testing facility in Mahendragiri, Tamil Nadu- and this time, it pushed the engine close to its maximum power.

The test involved Semi-Cryogenic Engine Power Head Test Article, or PHTA for short. PHTA can be considered as almost the entire engine, minus one major piece, the thrust chamber, which is the part that actually produces the flame and pushes the rocket upward.

By testing the rest of the engine's systems without this final component, Isro engineers can safely study how the engine builds up power and behaves under extreme conditions, before testing the complete engine.

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This was the eighth time Isro has tested this particular engine part, but it was the most ambitious test yet — and it cleared the bar with confidence.

What exactly did Isro test?

In simple terms, Isro tested how well the engine's internal machinery- pumps, ignition systems, and pressure systems, could perform when pushed to nearly full power.

Earlier tests had been conducted at lower power levels: 47 per cent and 60 per cent of the engine's full capacity. This time, engineers ramped it up dramatically to 175 tonnes of thrust, which is 88 per cent of the engine's total designed power of 200 tonnes. This is the first time the engine component has been tested at such a high level.

During the test, Isro also confirmed that the engine's turbopumps- essentially powerful pumps that feed fuel and oxidiser into the engine at extremely high pressure, worked exactly as expected, generating pressures of 400 and 500 bar. For comparison, a typical car tyre is inflated to about 2 bar, so this gives a sense of just how extreme the pressures inside a rocket engine really are.

Why does this matter?

According to Isro, the test went exactly as predicted, with all parameters behaving as expected. This gives engineers strong confidence that the engine can eventually be tested at its full 100 per cent thrust level of 200 tonnes, which is the next major milestone.

This engine isn't just a research exercise. It's a critical building block for the SE2000, a new and significantly more powerful engine that Isro is developing to replace the current engine system used in the LVM3, India's most powerful operational rocket.

What is this engine going to be used for?

The new engine will power something called the SC120 stage, which is designed to eventually replace the L110 stage currently used in the LVM3 rocket.

By swapping out the current L110 stage for the more powerful SC120 stage, Isro aims to significantly boost how much weight, or payload, the LVM3 can carry into space. This could mean larger satellites, more cargo for future missions, or capability for more ambitious space programmes, including crewed missions.

A cleaner way to fuel rockets

One particularly interesting detail is the type of fuel this new engine uses. Unlike some traditional rocket fuels that can be toxic and harder to handle, this semi-cryogenic engine runs on a combination of: Liquid Oxygen (LOX)- oxygen cooled to a liquid state, and Purified Kerosene, which Isro calls "isrosene"- a refined version of kerosene developed specifically for rocket use.

This propellant combination is considered cleaner, safer to handle, and more efficient compared to older systems, marking a shift toward more environmentally responsible rocket propulsion technology.