Hybrid Propulsion In-Situ Resource Utilization Test Facility Development

Abstract

Hybrid propulsion could be a potential game changing technology for several Mars applications, such as Mars Sample Return (MSR) and human exploration. A flexible hybrid test facility has been built at the Jet Propulsion Laboratory to provide data relevant to the design of such systems. This paper presents the motivations for such a system and its design. The facility is capable of testing 5 cm diameter fuel grains with gaseous oxygen and Mars in situ propellant production simulating oxidizer (varying mixtures of GO 2 , CO 2 and CO). All currently planned tests utilize paraffin based fuels; however, alternative hybrid fuels may be used in the future. Variable length to outer diameter (L/D) ratios may also be tested to give insight on potential packaging constraints. The goal of this research is to enable the inclusion of hybrid propulsion systems in future mission design studies by determining the empirical constants in the regression rate equation for paraffin-based fuels with space storable and/or in situ oxidizers and to investigate the effect of L/D on combustion efficiency. Test results will be reported separately. Nomenclature a = Regression Rate Coefficient G = Oxidizer Mass Flux [g/cm 2 s] Isp = Specific Impulse n = Regression Rate Exponent O/F = Oxidizer to Fuel Ratio ̇ = Regression Rate [mm/s]

Hybrid rocket propulsion systems for outer planet exploration missions

“…In recent years there has been increasing interest in using hybrid rocket motors for interplanetary missions [1,2]. Preliminary design studies have shown hybrid motors to be viable alternatives to conventional propulsion systems for some exploration missions [3][4][5][6].…”