Date of Award


Document Type


Degree Name

Master of Science in Astronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

Carl R. Hartsfield, PhD


This research explores metal post-processing techniques to effectively reduce the large anomalous protrusions found in small additively manufactured low thrust rocket nozzles. Research has found that nozzles of this kind can experience losses in thrust of over 40%. Analytic theory of adiabatic nozzle flow with viscous losses for additively manufactured nozzles does not align with what has been found when tested experimentally. Compressible flow losses, such as shock wave formation inside the nozzle diverging cone, are likely the leading causes of such loss. Reduction in nozzle irregularities can likely yield results seen in analytic theory with similar performance to traditional subtractive manufacturing methods for low thrust nozzle design. Methods such as abrasive flow machining, electro-polishing, milling, wire EDM skimming, and high-temperature coatings are investigated and tested experimentally to compare laboratory results to analytic theory and traditionally manufactured low thrust nozzles. Nozzle performance increases showed to be greater than 20% across various explored post-processing techniques.

AFIT Designator


DTIC Accession Number