AIAA 95-4079 Rocket-Induced Magnetohydrodynamic Ejector —A Single-Stage-to-Orbit Advanced Propulsion Concept

ROCKET-INDUCED MAGNETOHYDRODYNAMIC EJECTOR—A SINGLE-STAGE-TO-ORBITADVANCED PROPULSION CONCEPT John Cole, Jonathan Campbell, and Anthony RobertsonNASA Marshall Space Flight CenterMarshall Space Flight Center, Alabama Abstract During the atmospheric boost phase of a rocket trajectory, magnetohydrodynamic (MHD) principles can be utilized to augment the thrust by several hundred percent without the input of additional energy. The concept is an MIII) implementation of a thermodynamic ejector. Some ejector history is described and some test data showing the impressive thrust augmentation capabilities of thermodynamic ejectors are provided. A momentum and energy bal-ance is used to derive the equations to predict the MHD ejector performance. Results of these equa-tions are compared with the test data and then applied to a specific performance example. The rocket-induced MHD ejector (RIME) engine is described and a status of the technology and avail-ability of the engine components is provided. A top-level vehicle sizing analysis is performed by scaling existing MHD designs to the required flight vehicle levels. The vehicle can achieve orbit using conserva-tive technology. Modest improvements are suggested using recently developed technologies, such as super-conducting magnets, which can improve predicted performance well beyond those expected for current single-stage-to-orbit (SSTO) designs. Rocket Engine Nozzle Ejector (RENE) For those unfamiliar with ejectors, an example that may be somewhat familiar are the ejectors used on rocket engine test stands to test altitude nozzles. At one atmosphere, the plume does not fully fill the altitude nozzle. Flow separation occurs that can damage the nozzle. The usual remedy is to place the engine inside a large tube, called an ejector, with a diameter two or three times that of the engine nozzle exit. The exhaust blows the air out of the end of the ejector at supersonic velocities, and air enters the front of the ejector at somewhat less than Mach 1. With the resulting low pressure inside the ejector, the plume fully fills the nozzle.