3481. Flight Test Analysis of LOX/Propylene Upper Stage Engine

Paper

Abstract

The objective of this paper is to present testing and analysis of an early prototype upper stage engine which could be optimized and evolved into a second stage engine for a Nanosat Launch Vehicle (NLV). The NLV is designed to deliver a nominal 10 kg payload to LEO and is being developed by the California Launch Vehicle Education Initiative (CALVEIN), a partnership program between Garvey Spacecraft Corporation (GSC) and California State University, Long Beach (CSULB) [3].
The engine is pressure-fed and uses LOX/propylene as propellants. It is designed to operate at a chamber pressure of 1 MPa and provide a vacuum thrust of 2000 N. Propylene was chosen as a propellant because it provides a higher specific impulse than RP-1 with comparable density at cryogenic temperatures [16].
This paper presents a first iteration of the preliminary design intended for space operations with an expansion ratio of 70 as well as the testing of its sea level version with an expansion ratio of 4. The space engine is designed with targeted combustion efficiency of 95% and nozzle efficiency of 98%, corresponding to a specific impulse of 347 s.
A static fire test of the engine, shown in Figure 9, with expansion ratio of 4 has been conducted twice at sea level with a burn time of 15 seconds and 5 seconds, respectively. A flight test, shown in Figure 11, has also been conducted to test the capabilities of the engine. Recorded data will be used to assess previous assumed efficiencies and refine, if necessary, the shape of the nozzle and configuration of the injector. The next steps include implementing necessary changes to the engine to achieve better performance for future testing. This paper will also address ways to manage and reduce overall engine weight to improve performance.