Dragonfly Lander: Terrestrial Thermal Control Techniques on Titan, Saturn's Largest Moon

Abstract

Dragonfly is a NASA New Frontiers mission that will send a rotorcraft lander to Titan, Saturn's largest moon. Titan has low gravity and a dense atmosphere, making flight an ideal way to traverse its surface, but its atmosphere also provides a way to manage temperatures of Lander components. The atmosphere of Titan is mostly nitrogen, like Earth, and the pressure at the surface is similar, about 1.5 times Earth pressure. The Lander thermal control system (TCS) will use the atmosphere that Titan generously provides to distribute heat from its Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) using a fan, which is one method used to manage previous missions' MMRTGs on Earth. The temperature of Titan at its surface is nearly constant but extremely cold at 94 K, nearly as cold as liquid nitrogen, so the TCS will retain the excess heat from the MMRTG by enclosing the MMRTG and Lander with a layer of insulation. Lander internal components will survive and operate in Earth-similar atmospheric temperature and pressure, and thus mass-efficient terrestrial thermal control techniques will be utilized to keep component temperatures within allowable limits. Lander external components will experience Earth-similar pressure but at an extremely cold temperature, so terrestrial thermal control techniques will be used, albeit attenuated to account for the extreme temperature. This paper will provide an overview of these still-evolving thermal design details with a discussion of the thermal testing campaign.