The operating characteristics of a ducted rocket in the Mars atmosphere

Abstract

The Mars vehicle which can fly in the Mars atmosphere is necessary to do detailed surveys of the surface of Mars. This vehicle needs a propulsion engine which can work in the Mars atmosphere, mainly consisting of carbon dioxide. The ducted rocket is effective as propulsion engine, because it uses carbon dioxide as an oxidizer and combusts metal as fuel. This paper reports operating characteristics of a ducted rocket in the Mars atmosphere. pressure is about 0.7 kPa, the Mars density is about 0.015 kg/m 3 , the Mars temperature is about 240 K, and the main Mars atmosphere ingredient is carbon dioxide (more than 95%). The Mars atmosphere environment is considerably different from the earth atmosphere environment. The Mars vehicle needs a propulsion engine which can work in the Mars atmosphere, mainly consisting of carbon dioxide. It is known that the certain metal burns in carbon dioxide. Therefore, the development of the propulsion engine is possible if metal is used as fuel and carbon dioxide is used as an oxidizer. In the carbon dioxide-breathing engine using metal fuels for the Mars atmosphere, there are some problems, the supply method of powdered metal fuels, the stable combustion of metal fuels in the combustor, the degradation by the adhesion of the combustion products, etc. 1) To solve these problems, we suggest ducted rocket. In the ducted rocket, the metal fuels are changed to state of the gas in a primary combustor, and is sent into a second combustor. In the second combustor, the metal fuels are combusted with the carbon dioxide as an oxidizer. Because the metal fuels are supplied from state of the gas, the supply method of metal fuels is not a problem. The structure of the ducted rocket is simpler than those of the jet engine and the reciprocating engine. In the ducted rocket, it is considered that there is little degradation by the adhesion of the combustion products. The operating time of the ducted rocket becomes longer than the normal rocket, because the ducted rocket uses the Mars atmosphere as an oxidizer. It is considered that the ducted rocket is effective as propulsion engine for the Mars vehicle. The operating characteristics of a ducted rocket in the Mars atmosphere are obtained and the purpose of this study is to evaluate feasibility of the ducted rocket as the propulsion engine.