Progress on the Organic and Inorganic Modules of the Spacecraft Water Impurity Monitor, a Next Generation Complete Water Analysis System for Crewed Vehicles

The Dragonfly Mass Spectrometer (DraMS) is an instrument on the Dragonfly mission operating on the surface of the Titan, the Saturn’s largest moon. Titan's atmosphere is nitrogen rich and has surface atmospheric pressure of 147 kPa and temperature of 94 K. Since electronics cannot survive at these extreme temperatures, significant thermal isolation is needed between the electronics and the Titan atmosphere to maintain the components above their survival temperatures. However, the main electronic box (MEB) for the DraMS instrument dissipates significant amount of heat over small volume and a conventional conductive cooling approach cannot be used without significant mass additions. Instead, a fan cooled approach was chosen. Conditioned room-temperature air, supplied by the Dragonfly lander, will flow directly over the MEB’s boards during DraMS operational scenarios. A cooling air manifold is designed with the help of computational fluid dynamics (CFD) simulations to effectively distribute the flow over the actively cooled boards. Since the fan will operate at denser-than-Earth pressures on Titan but Earth-like pressures during ground testing, a thermal test was performed to verify the fan’s thermal performance (at varying levels of pressure) and compared against CFD predictions. This test was performed with a 3-D printed mockup of the MEB with heated metallic plates to simulate the circuit boards. This paper will discuss the analytical CFD work and the thermal tests performed to aid the development of the DraMS thermal/mechanical MEB design.