Qualification Testing of a High Performance Bipropellant Rocket Engine Using MON-3 and Hydrazine

Abstract

Qualification testing of a model R-4D-15DM high performance bipropellant rocket engine using nitrogen tetroxide (MON-3) and hydrazine (N2H4) propellants was conducted at Aerojet’s Redmond test facility. This rocket engine incorporates a chemical vapor deposited iridium lined rhenium combustion chamber, which provides a higher operating temperature capability than the previous generation of columbium (niobium) alloy combustion chambers. Other features include a patented pre-combustor and “step” for maximizing combustion efficiency and helmholtz resonators to suppress the first tangential combustion instability mode. The qualification program included functional, transportation shock, storage, thermal vacuum, vibration, and hot fire testing. 345 ambient starts, 327 hot restarts, and thermal limit testing in a hot restart condition were demonstrated during the qualification program. This rocket engine is designed to produce a nominal vacuum thrust of 100 lbf (445N), operate at a mixture ratio range of 0.75 to 1.2, with a total burn time exceeding 21,400 seconds. A specific impulse of 325-328 seconds was demonstrated using nitrogen tetroxide (MON-3) oxidizer and hydrazine (N2H4) fuel as propellants with a 300:1 nozzle expansion ratio.