Indian rocket developer demonstrates in-flight hybrid engine restart

(SpaceEnergy) Indian aerospace company Space Zone India has reported a successful in-flight restart of its experimental RRR-1 hybrid rocket engine during a launch from Tamil Nadu on 10 October.

The demonstration formed part of Mission RHUMI TWIN 2026, conducted from the Thiruvidanthai coastline near Chennai.

According to a company announcement issued on 12 October, the rocket completed a programmed propulsion sequence involving two powered phases separated by a controlled shutdown.

The engine initially fired for approximately nine seconds before shutting down for three seconds. It then reportedly reignited for another five seconds, completing a 17-second sequence comprising 14 seconds of powered operation.

Space Zone India said onboard instrumentation and tracking systems monitored the vehicle's trajectory and propulsion performance.

RRR-1 uses hybrid propulsion technology, combining solid fuel with a separately supplied oxidiser. Controlling oxidiser flow enables engine shutdown, while subsequent reignition requires additional ignition and combustion-management capabilities.

The company is investigating whether restart-capable hybrid propulsion could support future reusable launch vehicles, satellite launch systems and other spacecraft applications requiring multiple engine burns.

Space Zone India plans further static-fire and flight testing to assess ignition reliability, combustion stability and propulsion performance.

It is also preparing to approach investors and industrial partners to support larger restart-capable hybrid propulsion systems.

The company has not disclosed the engine's thrust, propellant composition, flight altitude or detailed test telemetry.