DEVELOPMENT OF A DEPLOYABLE DECELERATOR CONCEPT FOR SMALL MARS LANDERS

Abstract

Small exploration spacecraft and landers have proven to be scientifically useful and capable with missions such as Philae or Hayabusa 2. For the exploration of planetary bodies with atmospheres, novel and efficient entry, descent and landing (EDL) technologies are being explored. One of these concepts is the rigid deployable decelerator, which would be an alternative to existing EDL systems if proven to be feasible. For a Mars micro lander mission with an entry mass of 25 kg and a ballistic coefficient of 3:5 kg=m2, a concept for a deployable decelerator was developed. First, a flow-field analysis of different possible geometries of the deployed structure with Ansys Fluent was performed. From this, the pressure and temperature distribution and qualitatively the heat flux density along the profile wall of each geometry were determined. Subsequently, for a conical geometry, a design for a deployment mechanism was developed based on the umbrella concept, where a deployable structure spans a flexible thermally resistant cloth. The mechanism developed is a combination of folding parallelised struts, similar to an umbrella, and telescopic rods. Focusing on the strut structure and based on the results of the flow field analysis, with Ansys it was then investigated whether the design can in principle withstand the mechanical loads generated by the maximum dynamic pressure and how the temperature behind the deployed cloth is distributed under the maximum thermal load.