ISRO completes extended plasma thruster test for future satellite propulsion

On March 27, 2025, the Indian Space Research Organisation (ISRO) marked a significant milestone in satellite propulsion technology by concluding a 1000-hour endurance test of its 300-millinewton Stationary Plasma Thruster (SPT). Designed for integration into electric propulsion systems, the thruster aims to eventually replace traditional chemical propulsion in ISRO's future satellite platforms.

Electric propulsion systems offer substantial advantages, notably the potential for considerable reductions in satellite mass. This mass saving translates into greater capacity for communications payloads such as transponders. Utilizing xenon as a propellant, the system boasts a specific impulse that is at least six times higher than conventional chemical propulsion, a critical metric in propulsion performance.

The test, conducted at a full power level of 5.4 kilowatts, was carried out in a vacuum chamber to simulate space conditions. Engineers closely tracked the wear of electrode liners throughout the experiment. These erosion measurements are essential for accurately estimating thruster lifespan and optimizing satellite orbit control.

ISRO views this achievement as a key step toward the operational deployment of the electric propulsion system. The thruster is set to undergo in-orbit validation on the upcoming Technology Demonstration Satellite (TDS-01), where it will be used for both orbit raising and station-keeping maneuvers to geostationary orbit.