Thermal Decomposition of Ablating Gap Filler Material for Atmospheric Entry Heatshields

Sreevishnu Oruganti, Nagi N. Mansour, Marco Panesi, Francesco Panerai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Atmospheric entry heatshields conventionally follow a tiled configuration, where numerous tiles of ablative material are bonded by a gap-filler. Atmospheric entry missions with large capsules starting with the Mars Science Laboratories to the most recent Mars 2020 mission use Room Temperature Vulcanized Silicone (RTV) as the gap-filler. This work discusses the response of RTV to high-temperatures that include mass-loss and microstructure change due to pyrolysis. As RTV pyrolysis poses unique problems such as foaming, intumescence and formation of a glassy SiO2 layer, understanding these complex phenomena is crucial for developing robust and accurate material response models. In this paper, thermogravimetric analysis was conducted to quantify the mass-loss of RTV as it is heated to 1000 C, in inert atmosphere. The thermally degraded samples were imaged using environmental scanning electron microscopy elucidating the microstructural foaming in RTV. Additionally, in-situ scanning electron microscopy was carried out on spin-coated RTV samples to observe in-situ the microstructure change as a function of temperature. TGA results revealed large mass loss, and SEM showed that the initially non-porous virgin RTV undergoes a marked change in microstructure, ending as a highly porous char.

Original languageEnglish (US)
Title of host publicationAIAA AVIATION 2022 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624106354
DOIs
StatePublished - 2022
Externally publishedYes
EventAIAA AVIATION 2022 Forum - Chicago, United States
Duration: Jun 27 2022Jul 1 2022

Publication series

NameAIAA AVIATION 2022 Forum

Conference

ConferenceAIAA AVIATION 2022 Forum
Country/TerritoryUnited States
CityChicago
Period6/27/227/1/22

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Nuclear Energy and Engineering
  • Aerospace Engineering

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