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NASA NTRSDate not supplied

Pterodactyl: Thermal Protection System Design Methodology for a Flap Control System

As interest in non-traditional entry vehicles continues to grow, the need for a Thermal Protection System (TPS) analysis approach that can account for entry solutions with changing geometry and complicated flow dynamics becomes invaluable. The NASA Space Technology Mission Directorate (STMD) Pterodactyl project aims to accomplish this through examination of a flap controlled Adaptable, Deployable Entry Placement Technology (ADEPT)-style Deployable Entry Vehicle (DEV). This paper details an improved methodology for modeling the aerothermodynamic environment and initial TPS design for a flap control system integrated with a symmetric DEV. Improvements include i) the addition of an anchoring process that uses an increased fidelity aerodynamic solution to anchor the aerothermal environment predictions and ii) increased surface resolution, for the 1D heat transfer analysis, to isolate the hottest area on the flap that will require the thickest TPS. It was found that the anchoring process provided an improved aerothermal environment prediction. Additionally, this analysis demonstrated that there is a need for increased surface resolution in the 1D thermal analysis since the predicted location of the hottest point was significantly different than the location identified using very coarse surface resolution.

Zane B Hays↗

NASA NTRSDate not supplied

Pterodactyl: Effects of 3D Thermal Analysis on Thermal Protection System Design for a Flap Control System

NASA’s Pterodactyl project has investigated the use of a novel multi-flap control system to facilitate precision targeting of Deployable Entry Vehicles (DEVs) during atmospheric re-entry [1]. DEVs can be folded to fit within the limiting cross-sectional area of current launch systems. Once deployed, the vehicle expands and settles into a pre-determined blunt body shape. While DEVs provide a more efficient solution to increased payload sizes, the absence of a back shell does not allow for easy integration of reaction control systems, which have historically been used for guidance and control (G&C) of rigid aeroshells during entry. One DEV solution, called the Adaptable, Deployable Entry Placement Technology (ADEPT), employs mechanically deployed gores. This provided the Pterodactyl project with the opportunity to incorporate a rib-mounted, 8-flap control system for G&C. Each flap can deflect independently in and out of the hypersonic flow, requiring TPS for the flaps. Previous work within the Pterodactyl project utilized 1D thermal analysis to design the TPS. However, the Pterodactyl project was concerned that the base level tools for 1D thermal analysis were not accounting for the 3D effects of the large heating gradients along and across the flaps, the in-depth in-plane conductivity of the TPS and internal structure, and the effects of the small edge radii at the neck of the flaps. This paper discusses the methodology and results of a 3D thermal analysis of the flap control system. Additionally, the results from the 1D and 3D thermal analyses are compared. It is found that elements of the original design that resulted from the 1D analysis may be overly conservative, and implementation of a 3D thermal analysis indicated a reduction in TPS thickness is feasible. This result helps to reduce the mechanical integration complexity of the flap at the rib tip and realizes potential mass savings.

Sarah N D'Souza↗