Investigation of biowaste resistojets for space station application
The feasibility of using electrically conducting ceramics to heat biowaste propellants to 2000 K in resistojet thrustors was demonstrated. These thrustors are being developed for use on the space station. Among the candidate ceramic heater materials, zirconia and thoria are chemically resistant to the biopropellants, and they are also sufficiently conductive at high temperatures to make them suitable for the heater elements in these thrustors. A proof of concept thrustor design is presented, incorporating a multiple passage cylindrical heater made of zirconia ceramic which is capable of operating at 2000 K wall temperature with CO2 and H2O biopropellants. For the 25 mlb size thrustor, specific impulses of 200 seconds for CO2 and 275 seconds for H2O biopropellants are predicted.