The Indian Space Research Organisation (ISRO) is planning to launch its first LVM3 rocket equipped with a semi-cryogenic propulsion stage in 2027.

The LVM3, also known as the Geosynchronous Satellite Launch Vehicle MK-III (GSLV MK-III), is currently a three-stage heavy-lift launch vehicle that had its first experimental flight in December 2014. It is ISRO's most powerful rocket to date, capable of carrying payloads up to 4,200 kg to geosynchronous transfer orbit (GTO).

The development of the three-stage Launch Vehicle Mark-3 (LVM3), also known as GSLV MK-III, marked a significant milestone for the Indian Space Research Organisation (ISRO) with its first experimental flight taking place in December 2014. This launch was a pivotal step in the advancement of India’s indigenous heavy-lift launch capabilities.

The LVM3 was designed to address the increasing demand for launching heavier payloads into geostationary transfer orbit (GTO) and beyond, thereby enhancing the country’s satellite deployment efficiency for communication, navigation, and scientific missions.

The major upgrade involves replacing the existing L110 core stage, which uses a liquid propellant powered by the Vikas engine with about 80 tonnes of thrust, with a new semi-cryogenic stage called SC120.

This stage uses a more efficient propellant combination of refined kerosene and liquid oxygen (LOX) powered by the SE2000 engine designed to deliver about 200 tonnes of thrust. The cryogenic upper stage, which uses liquid hydrogen and LOX, will also be uprated with an increased propellant loading from 28 tonnes to 32 tonnes.

This semi-cryogenic propulsion system combined with the upgraded cryogenic upper stage will enhance the LVM3's payload capability significantly—from the current 4,200 kg to about 5,200 kg to GTO. Additionally, this upgrade is expected to reduce the cost of placing satellites into orbit by approximately 25%.

The SE2000 semi-cryogenic engine is a complex engine developed by ISRO’s Liquid Propulsion Systems Centre. It features an oxidizer-rich staged combustion cycle using non-toxic propellants (liquid oxygen and kerosene), which improves performance and reduces environmental hazards compared to the existing hydrazine-based systems.

The engine development has achieved key milestones, including successful power head tests and integrated hot tests at the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu. The new semi-cryogenic stage and engine system are expected to not only enhance LVM3 but also be utilized in future ISRO launch vehicles, boosting India's heavy-lift capabilities in space missions.

The semi-cryogenic powered LVM3 will therefore represent a significant step forward in ISRO's launch vehicle technology, providing increased payload capacity, cost-efficiency, and environmentally safer propulsion. The launch is scheduled for the first quarter of 2027, with ongoing testing and development on track to meet this timeline.

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