Conflicting Design Issues Hallmark the Compound Rocket Motors

Abstract

A series of conflicting requirements to which the design of the compound rocket motors are subjected are considerably diminishing the efficiency of that type of rocket motors. The necessity of delivering a high thrust level at lift-off and during the sustainer phase up to optimal velocity accommodation, coupled with the requirement for a slander body configuration for air drag mitigation during the atmospheric ascent are the dominant issues that end into a compromise that lower the overall efficiency to a great extent, in comparison the available theoretical performance of compound rocket motors. The optimal design is imposing a lower mass ratio that expected and is the main cause of efficiency reduction when very high velocity requirements are searched for, like in orbital launchers. However, the margins of propulsive efficiency build-up can be conveniently manipulated through geometrical optimization and attentive risk management of the propulsion system as shown by the experimental results protruded during the development of the NERVA-ORVEAL space rocket motor.

Orbital Launcher NERVA as the First Proof of the Discontinuous Variational Solution for the Atmospheric Ascent

“…The blend [17] of triple-base propellant (NC-NG-DNT + additives) type A-100 supplies a see level specific impulse of 2200 m/s at a convenient burning temperature of 2250°K. Upgrading is envisaged however through the innovative compound rocket engine (CRE) solution [14,15,16].…”