The Indian Space Research Organisation (ISRO) has achieved a significant milestone by employing electromechanical actuators for the first time in the first stage of its LVM-3 rocket. This innovation was demonstrated during the successful LVM-3-M6 mission, which orbited the American BlueBird Block-2 satellite on 24 December 2025.

Dr V Narayanan, Chairman of ISRO and Secretary to the Department of Space, confirmed the deployment during a briefing in Bangalore on 25 December. The actuators controlled the gimballing of the S200 solid strap-on booster nozzles, marking a departure from the previous electrohydraulic systems used in earlier missions.

Electromechanical actuators operate using a brushless DC electric motor coupled with a mechanical gear or ball screw system to extend or retract the engine nozzle. This design offers simplicity, ease of testing and integration, and reduced weight compared to hydraulic alternatives, as explained by Dr S Unnikrishnan, former Director of Vikram Sarabhai Space Centre (VSSC) and current Distinguished Professor there.

In contrast, electrohydraulic actuators rely on an electric motor driving an internal hydraulic pump to generate substantial force. While they provide robust power and resistance to jamming due to lubrication, they are heavier, bulkier, and susceptible to leaks or debris contamination during assembly.

ISRO had previously adopted electromechanical actuators across most stages of its launch vehicles, excluding the S200 boosters in LVM-3's first stage. The switch in this critical component introduces no substantial impact on the rocket's overall payload capacity, given that mass sensitivity is lower in the initial phase.

The LVM-3 remains a three-stage medium-lift vehicle, featuring two S200 solid strap-on motors, a liquid L110 core stage, and a C25 cryogenic upper stage. It boasts a lift-off mass of 640 tons, a height of 43.5 metres, and capacities of approximately 4 tons to Geosynchronous Transfer Orbit (GTO) and 10 tons to Low Earth Orbit (LEO), with ongoing efforts to enhance GTO performance to 5 tons.

A Rajarajan, Director of VSSC, highlighted that the electromechanical actuators yield a payload gain of about 85 kg per stage alongside fewer parts, facilitating pre-testing and readiness. ISRO Chairman Narayanan noted a similar improvement of roughly 150 kg in total payload capability for the LVM-3 upgrade program.

These actuators play a pivotal role in thrust vector control, aligning nozzles for precise guidance and stability during ascent. The LVM-3-M6 mission, launched within a tight 52-day interval from the prior flight, underscores ISRO's enhanced operational tempo and readiness for demanding campaigns like Gaganyaan.

To bolster production, ISRO identified twelve types of electromechanical actuators for PSLV, GSLV, and LVM-3 under a Government-Owned Company-Operated (GOCO) model. Private firms such as Hical Technologies in Bangalore have realised flight-grade units at a dedicated VSSC facility.

The VSSC facility, operational since 6 January 2021, includes bonded stores, fitting shops, assembly areas, inspection zones, and a Class-1000 clean room equipped with electrical, mechanical tools, test fixtures, and checkout systems. This infrastructure supports scalable manufacturing for space, defence, and aeronautics applications.

The adoption aligns with broader LVM-3 enhancements, including human-rated variants for Gaganyaan, featuring high-thrust Vikas engines, reinforced S200 boosters with triple O-rings, and digital controllers across stages. Electro-mechanical gimbal systems have already been qualified in related Vikas engine tests.

This breakthrough not only optimises mass and reliability but also strengthens India's self-reliance in propulsion control technologies, paving the way for more frequent, cost-effective launches amid growing commercial demands.

Based On UNI Report

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