David J. Kinney

Adaptive Deployable Entry and Placement Technology (ADEPT): A Feasibility Study for Human Missions to Mars

The present paper describes an innovative, semi-rigid, mechanically deployable hypersonic decelerator system for human missions to Mars. The approach taken in the present work builds upon previous architecture studies performed at NASA, and uses those findings as the foundation to perform analysis and trade studies. The broad objectives of the present work are: (i) to assess the viability of the concept for a heavy mass (landed mass ≈40 mT) Mars mission through system architecture studies; (ii) to contrast it with system studies previously performed by NASA; and (iii) to make the case for a Transformable Entry System Technology. The mechanically deployable concept at the heart of the proposed transformable architecture is akin to an umbrella, which in a stowed configuration meets launch requirements by conforming to the payload envelope in the launch shroud, and when deployed in earth orbit forms a large aerosurface designed to provide the necessary aerodynamic forces upon entry into the Martian atmosphere. The aerosurface is a thin skin draped over high-strength ribs; the thin skin or fabric with flexible material serves as the thermal protection system, and the ribs serve as the structure. A four-bar linkage mechanism allows for a reorientation of the aerosurface during aerocapture or during the entry and descent phases of atmospheric flight, thus providing a capability to navigate and control the vehicle and make possible precision landing. The actuators and mechanisms that are used to deploy the aerosurface are multi-functional in that they also allow for reorienting the

Overview of the NASA Entry, Descent and Landing Systems Analysis Study

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the approach and top-level results from Year 1 of the Study, which focused on landing 10–50 mt on Mars, but also included a trade study of the best advanced parachute design for increasing the landed payloads within the EDL architecture of the Mars Science Laboratory (MSL) mission.

TPS SELECTION AND SIZING TOOL IMPLEMENTED IN AN ADVANCED ENGINEERING ENVIRONMENT

A tool, TPSSIZER, was developed to provide a Thermal Protection System (TPS) analysis and design capability . The tool focuse d on analysis of space vehicles at the conceptual design level and was implemented in a collaborative engineering analysis environment. TPS sizing methodologies and data exchange interfaces with supporting disciplines were developed. Additionally, improv ements were made to prior art by introducing automatic generation of TPS stackups, automatic generation of aerothermal environment files, maintenance of consistent material properties descriptions, and the capability to simultaneously ev aluate multiple nom inal and abort flight trajectories .

An Integrated Vehicle Modeling Environment

This paper describes an Integrated Vehicle Modeling Environment for estimating aircraft geometric, inertial, and aerodynamic characteristics, and for interfacing with a high fidelity, workstation based flight simulation architecture. The goals in developing this environment are to aid in the design of next generation intelligent fight control technologies, conduct research in advanced vehicle interface concepts for autonomous and semi-autonomous applications, and provide a value-added capability to the conceptual design and aircraft synthesis process. Results are presented for three aircraft by comparing estimates generated by the Integrated Vehicle Modeling Environment with known characteristics of each vehicle under consideration. The three aircraft are a modified F-15 with moveable canards attached to the airframe, a mid-sized, twin-engine commercial transport concept, and a small, single-engine, uninhabited aerial vehicle. Estimated physical properties and dynamic characteristics are correlated with those known for each aircraft over a large portion of the flight envelope of interest. These results represent the completion of a critical step toward meeting the stated goals for developing this modeling environment.

An Asymmetric Capsule Vehicle Geometry Study for CEV

An asymmetric heatshield configuration named Asymmetric Capsule Vehicle, intended for use as the basis for an atmospheric entry, is introduced. The aerodynamic and aerothermodynamic behavior of this new class of heatshield geometries is examined in the supersonic and hypersonic flow regimes using both high-fidelity and engineering analysis techniques, and compared to the performance of heatshields derived from the asymmetric Aeroassist Flight Experiment (AFE) and the symmetric Apollo configurations. The geometry of this new class of heatshield is described analytically and involves a small set of parameters suitable for inclusion in an optimization process. Two particular optimized configurations, the ACVOpt and ACVeOpt2 heatshield shapes, prove to have ‐ (1) higher L/D aerodynamic performance, and (2) lower convective and radiative heating compared to the Apollo-derived symmetric shape. These configurations also do not have the supersonic trim stability issue found to occur with the asymmetric AFE-derived shape.

Overview of the NASA Entry, Descent and Landing Systems Analysis Studies for Large Robotic-class Missions

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis Study in 2008 to identify and roadmap the Entry, Descent and Landing technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the approach and top-level results from Year 2 of the Study, which focused on landing 1‐4 mt on Mars for robotic missions. Two separate studies were conducted in Year 2: the Mars Science Laboratory Improvement Study, which determined technology development program needs to support increases in landed payload and landed altitude beyond the Mars Science Laboratory capability using an Atlas V launch vehicle and the Exploration Feed-Forward Study, which examined a potential precursor mission using a Delta IV-H launch vehicle with landed payload in the 2‐4 mt range that would demonstrate key technologies needed for later human missions.

Human Mars mission design study utilizing the adaptive deployable entry and placement technology

The Adaptive Deployable Entry and Placement Technology (ADEPT) is being considered as an entry, descent and landing (EDL) system to enable Human Mars class missions. ADEPT is a mechanically deployable decelerator that makes use of a 3 d woven carbon fabric as both heat shield and primary structure. The Human Mars Mission design study is focused, in part, on assessing the viability of ADEPT and identifying technical challenges, operational constraints, and critical risk mitigation activities. Study inputs included definition of the ground rules and assumptions, associated mission timelines and high level functional requirements. These inputs enabled the clarification of the concept of operations along with the design constraints and environments. Subsystem trades, mass sizing and integrated flight performance assessments enabled determination of a feasible mission architecture. Key outputs from the design study include a parametric mass model, driving requirements, key performance parameters and critical risks. These findings enable us to determine strategies for technical maturation and risk mitigation that can be assessed against resource and programmatic constraints to aid in advanced planning for human exploration of Mars.

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

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.