Pterodactyl: System Analysis of an Asymmetric and Symmetric Deployable Entry Vehicle for Precision Targeting Using Flaps

摘要

The current state-of-the-art for entry control systems is rooted in heritage entry, descent, and landing (EDL) systems such as Apollo and Mars Science Laboratory. These rigid entry vehicles used Reaction Control System (RCS) thrusters, installed within the backshell, to achieve the desired bank command profile [1]. In recent years, NASA has invested in game changing entry vehicle technologies, including the Deployable Entry Vehicles (DEV) concept. DE Vs are radically different from rigid entry vehicles because DEVs have no backshell, making unavailable the typical locations for installation of RCS thrusters and associated fuel lines. In order to overcome this challenge, aerodynamic control systems are being considered as the primary means of entry precision targeting for DEVs. These control systems have been shown to enable precision targeting for DEV's and have the potential to save propellant mass and payload volume. In this work, the Pterodactyl project compares the mechanical feasibility and targeting performance of an aerodynamic control system (flaps) installed on two variants of a mechanically deployed DEV technology called the Adaptable, Deployable, Entry and Placement Technology (ADEPT). The two DEV variants are as follows; the Pterodactyl Baseline Vehicle Ⅰ (PBV-Ⅰ), which has an asymmetric aeroshell and PBV-Ⅱ which has a symmetric aeroshell. The performance of each vehicle configuration is discussed based on specific parameters: mechanical feasibility, range capability, flap usage, and robustness to aerodynamic roll dispersions. This paper details the advantages and challenges of PBV-Ⅰ and PBV-Ⅱ to understand their breadth of capability to command bank and/or alpha/beta guidance profiles.