Yuen Liu

Date of Award


Document Type


Degree Name

Master of Science in Astronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

Carl Hartsfield, PhD.


The purpose of this research is to develop new nozzles for the HYDROSTM thruster, a pulsed chemical thruster, to improve the current flight performance. This research consists of a base line test of the factory nozzle, as well as testing of three 15-degree conical nozzles with different expansion ratios. Experiments were conducted at plenum pressures 30, 40, and 45 psia to ensure the thruster is throttleable. Impulse bit data was collected through measuring the impulse response of each firing using a torsional balance thrust stand. Analysis of the thruster performance included calculations of impulse bit, specific impulse, thrust coefficient, and exhaust plume attachment. Experimental data showed that the smaller expansion ratio nozzles have a higher performance than the larger expansion ratio nozzles. This agrees with previous research from NASA that the benefit from the increase in area ratio does not overcome the increased viscous losses due to the increase in surface area for small throat areas.

AFIT Designator


DTIC Accession Number