30kN Hybrid Motor on Test Bed (L) and Hot Test under progress

ISRO has successfully tested a hybrid motor at ISRO Propulsion Complex (IPRC), Mahendragiri, supported by Liquid Propulsion Systems Centre. The motor used Hydroxyl-Terminated Polybutadiene (HTPB) as fuel and liquid oxygen (LOX) as the oxidizer. Unlike solid-solid or liquid-liquid combinations, a hybrid motor uses solid fuel and liquid oxidizer.

Today’s test of a flight equivalent 30 kN hybrid motor demonstrated ignition and sustained combustion for the intended duration of 15 seconds. The motor performance was satisfactory.

Source: ISRO       
The use of liquids facilitates throttling and the control over the flow rate of LOX enables the re-start capability.

While both HTPB and LOX are green, LOX is safer to handle. The hybrid motor tested today is scalable and stackable, potentially paving the way for a new propulsion system for the forthcoming launch vehicles.