The Indian Space Research Organisation (ISRO) has held detailed technical discussions with Russia’s space agency Roscosmos in Moscow regarding the delivery of semi-cryogenic rocket engines. 

According to ISRO’s Annual Report for 2025–26, a draft contract for the procurement is currently under the approval process, marking a significant step forward in India’s efforts to strengthen its launch vehicle capabilities.

The semi-cryogenic engine technology, which uses refined kerosene and liquid oxygen, is considered vital for India’s future heavy-lift launch vehicles. This combination offers higher efficiency and thrust compared to existing propulsion systems, enabling India to carry heavier payloads and undertake ambitious deep space missions.

The induction of such engines is expected to enhance India’s competitiveness in the global space sector.

While India has been developing its own semi-cryogenic engine programme, collaboration with Roscosmos could help accelerate timelines and bridge critical technological gaps. The Annual Report did not specify the delivery schedule or contract finalisation date, but the approval stage indicates that negotiations have moved beyond preliminary discussions.

ISRO had earlier announced on 28 March 2025 that it achieved a major breakthrough in semi-cryogenic engine development when the first successful hot test of the Engine Power Head Test Article (PHTA) was conducted at the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu. The Liquid Propulsion Systems Centre (LPSC) is leading the development of the semi-cryogenic propulsion engine and stage.

The SC120 stage, powered by the 2000 kN semi-cryogenic engine designated SE2000, is designed to replace the current L110 core liquid stage of the LVM3 rocket. This upgrade will enhance payload capacity and also serve as a booster stage for future launch vehicles.

ISRO has emphasised that the use of non-toxic and non-hazardous propellants such as liquid oxygen and kerosene will deliver higher performance compared to the existing L110 stage.

With the induction of semi-cryogenic propulsion and an uprated cryogenic stage, the LVM3’s payload capability in geosynchronous transfer orbit (GTO) will increase from 4 tonnes to 5 tonnes. The SE2000 engine incorporates advanced subsystems including a thrust chamber, pre-burner, turbo pump system, control components, and a start-up system. It operates on a complex oxidiser-rich staged combustion cycle with a chamber pressure of 180 bar, propellant feed pressures up to 600 bar, and a specific impulse of 335 seconds.


The development of such high-thrust engines is highly challenging and remains limited to only a few nations. India’s pursuit of this technology underscores its ambition to achieve greater self-reliance in advanced rocketry.

However, indigenous development of the SE2000 engine is still years away from flight readiness, making procurement from Russia a practical interim solution. Reports since 2023 have consistently pointed to the RD-191 engine, developed by Russia’s NPO Energomash and used in the Angara rocket series, as the likely candidate for India’s procurement. The RD-191 is throttleable, allowing precise flight control and enabling recovery and reuse of rocket stages, which aligns with ISRO’s long-term vision for reusable launch vehicles.

India’s Parliamentary Standing Committee on Science and Technology has also allocated funds in 2026–27 for the induction of procured semi-cryogenic engines to expedite enhancement of LVM3’s payload capacity. This reflects the government’s commitment to supporting ISRO’s technological advancement.

The Moscow visit forms part of ISRO’s broader international engagements over the past year. The Annual Report noted that ISRO has been in talks with multiple countries on areas including human spaceflight, satellite navigation, earth observation, and capacity building.

ISRO’s cooperation with Russia extends beyond propulsion systems. The report highlighted that Russia’s Space Research Institute has been selected as a partner payload provider for India’s planned Venus Orbiter Mission (VOM).

The mission aims to study Venus’s atmosphere, ionosphere, surface, subsurface, and solar interactions. Approvals were secured in April 2025 for international collaborations, including an MoU with Roscosmos for the Venus InfraRed Atmospheric gases Linker (VIRAL) payload and another with the Swedish Institute of Space Physics for the VNA payload.

The Science Working Group has been constituted to maximise scientific returns from the mission, and the Principal Scientist has been declared. The Preliminary Design Review of the Venus Orbiter Mission has also been completed, marking progress towards its eventual launch.

Together, these developments highlight India’s dual-track approach: advancing indigenous propulsion technology while strategically collaborating with international partners to accelerate capability building. 

The semi-cryogenic engine procurement from Russia, once finalised, will represent a milestone in Indo-Russian space collaboration and reinforce India’s trajectory towards greater autonomy in advanced rocket technology.

ANI