A Rigid Mid Lift-to-Drag Ratio Approach to Human Mars Entry, Descent, and Landing

Abstract

Current NASA Human Mars architectures require delivery of approximately 20 metric tons of cargo to the surface in a single landing. A proposed vehicle type for performing the entry, descent, and landing at Mars associated with this architecture is a rigid, enclosed, elongated lifting body shape that provides a higher lift-to-drag ratio (L/D) than a typical entry capsule, but lower than a typical winged entry vehicle (such as the Space Shuttle Orbiter). A rigid Mid-L/D shape has advantages for large mass Mars EDL, including loads management, range capability during entry, and human spaceflight heritage. Previous large mass Mars studies have focused more on symmetric and/or circular cross-section Mid-L/D shapes such as the ellipsled. More recent work has shown performance advantages for non-circular cross section shapes. This paper will describe efforts to design a rigid Mid-L/D entry vehicle for Mars which shows mass and performance improvements over previous Mid-L/D studies. The proposed concept, work to date and evolution, forward path, and suggested future strategy are described.

Mid-Lift-to-Drag Ratio Rigid Vehicle Control System Design and Simulation for Human Mars Entry

“…Previous 3-DOF trajectories utilized perfect control, but there was no way to simulate an RCS thrust acceleration 3 Because of this, a pseudo-1-DOF controller that emulates an applied bank acceleration and rate limit was created. Monte Carlo dispersions on angular accelerations and rate limits influenced RCS jet design and requirements.…”

“…Aerodynamic moment coefficients for the Mid-L/D were generated at various angles of attack ( ) and sideslip angles ( ) from Mach 12 to 2 using the Cart3D CFD analysis tool. 3 The moment is transferred from the aerodynamic moment reference center (MRC) at the nose and applied to the CG as shown in Figure 5. …”