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At least 235 records · Page 13

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NASA NTRS2013

Flight Performance Feasibility Studies for the Max Launch Abort System

In 2007, the NASA Engineering and Safety Center (NESC) initiated the Max Launch Abort System Project to explore crew escape system concepts designed to be fully encapsulated within an aerodynamic fairing and smoothly integrated onto a launch vehicle. One objective of this design was to develop a more compact launch escape vehicle that eliminated the need for an escape tower, as was used in the Mercury and Apollo escape systems and what is planned for the Orion Multi-Purpose Crew Vehicle (MPCV). The benefits for the launch vehicle of eliminating a tower from the escape vehicle design include lower structural weights, reduced bending moments during atmospheric flight, and a decrease in induced aero-acoustic loads. This paper discusses the development of encapsulated, towerless launch escape vehicle concepts, especially as it pertains to the flight performance and systems analysis trade studies conducted to establish mission feasibility and assess system-level performance. Two different towerless escape vehicle designs are discussed in depth: one with allpropulsive control using liquid attitude control thrusters, and a second employing deployable aft swept grid fins to provide passive stability during coast. Simulation results are presented for a range of nominal and off-nominal escape conditions.

Tarabini, Paul V.↗

NASA NTRS1989

Two-tiered design analysis of a radiator for a solar dynamic powered Stirling engine

Two separate design approaches for a pumped loop radiator used to transfer heat from the cold end of a solar dynamic powered Stirling engine are described. The first approach uses a standard method to determine radiator requirements to meet specified end of mission conditions. Trade-off studies conducted for the analysis are included. Justification of this concept within the specified parameters of the analysis is provided. The second design approach determines the life performance of the radiator/Stirling system. In this approach, the system performance was altered by reducing the radiator heat transfer area. Performance effects and equilibrium points were determined as radiator segments were removed. This simulates the effect of loss of radiator sections due to micro-meteoroid and space debris penetration. The two designs were compared on the basis of overall system requirements and goals.

Hainley, Donald C.↗

NASA NTRS1989

Two-tiered design analysis of a radiator for a solar dynamic powered Stirling engine

Two separate design approaches for a pumped loop radiator used to transfer heat from the cold end of a solar dynamic powered Stirling engine are described. The first approach uses a standard method to determine radiator requirements to meet specified end of mission conditions. Trade-off studies conducted for the analysis are included. Justification of this concept within the specified parameters of the analysis is provided. The second design approach determines the life performance of the radiator/Stirling system. In this approach, the system performance was altered by reducing the radiator heat transfer area. Performance effects and equilibrium points were determined as radiator segments were removed. This simulates the effect of loss of radiator sections due to micro-meteoroid and space debris penetration. The two designs are compared on the basis of overall system requirements and goals.

Hainley, Donald C.↗

NASA NTRS1991

Structural design considerations for the Space Infrared Telescope Facility

To assess the design feasibility of the Space Infrared Telescope Facility (SIRTF) and to identify parameters that might impose constraints on performance such as frequencies of vibration, structural concepts for both the telescope and spacecraft are developed and evaluated. Trade studies of key design features are carried out using FEM and analysis. In most cases, the margin of safety was greater than 0.50. An example of stress in the octagonal equipment bus panels is shown. The strap-supported mass is predicted to deflect 6 mm relative to the outer shell when subjected to 8.0 G in the X direction, and to deflect about 5 mm in the Y and Z directions when subjected to 10.0 G. Deflections for the top of the solar panel are predicted to be about 35 mm when subjected to the 10.0 G quasi-static load in the Z direction. The liquid helium tank, thermal isolation, and primary mirror and mount are discussed.

Macneal, Paul D.↗

NASA NTRS2005

In-situ Resource-based Lunar and Martian Habitat Structures Development at NASA/MSFC

As the nation prepares to return to the Moon and subsequently to Mars, it is apparent that the viability of long duration visits with appropriate radiation shielding/crew protection, hinges on the development of habitat structures, preferably in advance of a manned landing, and preferably utilizing in-situ resources. A relatively large number of habitat structure configurations can be developed from a relatively small set of in-situ resource-based construction products, including, blocks, raw regolith, reinforced concrete, and glass products. A much larger group of habitat designs can be developed when "imported" material are brought from Earth, including thin films and liners, and foldable, or expandable metal structures. These, and other technologies have been identified, and subjected to a rigorous trade study evaluation with respect to exploration and other performance criteria. In this paper, results of this trade study will be presented, as well as various habitat structure design concepts and concepts for construction automation. Results of initial tests aimed at concrete, block and glass production using Lunar regolith simulants will also be presented. Key issues and concerns will be discussed, as well as design concepts for a Lunar environment testbed to be developed at MSFC's Microgravity Development Laboratory (MDL).

Bodiford, Melanie P.↗

NASA NTRS2005

In Situ Resource-Based Lunar and Martian Habitat Structures Development at NASA/MSFC

Bodiford, Melanie P.↗

NASA NTRS1998

Development of a Woven-Grid Quasi-Bipolar Battery

This report describes an analytical and experimental investigation of AeroVironment's Quasi-Bipolar battery concept. The modelling/battery design part of the study demonstrates that there is a trade-off between thermal and specified electrical performance. Even so, quasi-bipolar batteries can be designed, with ten times better thermal uniformity, that meet or exceed current state-of-the-art hybrid-electric vehicle battery pack performance, even using the same active materials. The thermal uniformity, power, and energy for these quasi-bipolar battery packs is projected to be very good. The experimental part of the investigation demonstrates the concept of the quasi-bipolar plate applied to a lead foil current collector wrapping around two sides of an inexpensive plastic film core. Approximately 50 quasi-biplate samples were fabricated using a hot laminating press. Hot lamination with "texture" between the plastic and lead shows some promise as a low cost method for fabricating the plates. Five of these plates were assembled into two cells plus one two-cell battery. Data from these test cells were compared with existing data for similar true bipolar batteries. The positive side of the plates exhibited corrosion where not protected by the active material.

Tokumaru, P.↗

NASA NTRS1982

Advanced 30/20 GHz multiple-beam antennas for communications satellites

Design concepts under development utilize two separate spacecraft antenna systems, one uplink at 30 GHz and the other a downlink at 20 GHz, where each antenna provides multiple fixed and scanning beams. Two contractors completed configuration trade-off studies and breadboarding of critical technology components, and are fabricating and testing proof-of-concept (POC) models to demonstrate the technology feasibility. Technology developments required for the proposed systems are presented, along with each contractor's progress to date. The technology development areas discussed include: (1) offset Cassegrain and shaped reflector systems for narrow beams with low sidelobes and wideangle off-axis scan; (2) diplexed beam-forming networks for dual polarization, low sidelobes, and fixed and scan-beam operation; (3) fast switching networks for scanning beams; and (4) fabrication of precision feed components and large offset reflectors.

Myhre, R. W.↗

NASA NTRS1983

Advanced 30/20 GHz multiple-beam antennas for communications satellites

Myhre, R. W.↗

NASA NTRS1991

Consolidation of graphite thermoplastic textile preforms for primary aircraft structure

The use of innovative cost effective material forms and processes is being considered for fabrication of future primary aircraft structures. Processes that have been identified as meeting these goals are textile preforms that use resin transfer molding (RTM) and consolidation forming. The Novel Composites for Wing and Fuselage Applications (NCWFA) program has as its objective the integration of innovative design concepts with cost effective fabrication processes to develop damage-tolerant structures that can perform at a design ultimate strain level of 6000 micro-inch/inch. In this on-going effort, design trade studies were conducted to arrive at advanced wing designs that integrate new material forms with innovative structural concepts and cost effective fabrication methods. The focus has been on minimizing part count (mechanical fasteners, clips, number of stiffeners, etc.), by using cost effective textile reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low-cost resin transfer molding processing, and thermoplastic forming concepts. The fabrication of representative Y spars by consolidation methods will be described. The Y spars were fabricated using AS4 (6K)/PEEK 150g commingled angle interlock 0/90-degree woven preforms with +45-degree commingled plies stitched using high strength Toray carbon thread and processed by autoclave consolidation.

Suarez, J.↗

NASA NTRS2016

Passive vs. Parachute System Architecture for Robotic Sample Return Vehicles

The Multi-Mission Earth Entry Vehicle (MMEEV) is a flexible vehicle concept based on the Mars Sample Return (MSR) EEV design which can be used in the preliminary sample return mission study phase to parametrically investigate any trade space of interest to determine the best entry vehicle design approach for that particular mission concept. In addition to the trade space dimensions often considered (e.g. entry conditions, payload size and mass, vehicle size, etc.), the MMEEV trade space considers whether it might be more beneficial for the vehicle to utilize a parachute system during descent/landing or to be fully passive (i.e. not use a parachute). In order to evaluate this trade space dimension, a simplified parachute system model has been developed based on inputs such as vehicle size/mass, payload size/mass and landing requirements. This model works in conjunction with analytical approximations of a mission trade space dataset provided by the MMEEV System Analysis for Planetary EDL (M-SAPE) tool to help quantify the differences between an active (with parachute) and a passive (no parachute) vehicle concept.

Maddock, Robert W.↗

NASA NTRS1994

Self Assembling Mars Transfer Vehicles: The Preferred Concept of the Space Transfer Concepts and Analysis for Explorations Missions Study

Recently, one of the most comprehensive design studies of conceptual manned Mars vehicles, conducted since the Apollo era Mars mission studies of the 1960's, was completed. One of the tasks of the study involved the analysis of nuclear thermal propulsion spacecraft for Manned Mars exploration missions. This paper describes the specific effort aimed at vehicle configuration design. Over the course of the four year study, three configuration baselines were developed, each reflecting trade study cycle results of sequential phases of the study. Favorable attributes incorporated into the final concept, including a capability for on-orbit self-assembly and ease of launch vehicle packability, represent design solutions to configuration deficiencies plaguing nuclear propulsion Mars spacecraft design since the vehicle archetype originated in the 1950's. This paper contains a narrative summary of significant milestones in the effort, describes the evolution to the preferred configuration, and set forth the benefits derived from its utilization.

Donahue, Benjamin↗

NASA NTRS2023

Automated Medical Inventory System (AMIS) TechPort Entry

The current medical inventory paradigm on the International Space Station (ISS) requires crew to report use of medications and supplies to be manually decremented by ground teams. This method is not only tedious and time consuming for both the crew and ground teams but also results in inaccuracies in location and availability of medical supplies over time. Fortunately, the ISS is frequently resupplied by cargo launches and crew expeditions, and an accurate inventory count is less critical. However, for exploration missions, resupply will be greatly limited or unavailable entirely, and increasing communication latency will impair crew-ground communications. On longer missions, with large medical systems and time constrained crew, NASA needs a method of accurately managing medical inventory without reliance on ground teams and with as little crew time and effort as possible. The Exploration Medical Integrated Product Team (XMIPT) project called Medical Exploration Development and Implementation Scoping (MEDIScope) prepared a concept of operations and preliminary requirements for an Automated Medical Inventory System (AMIS) and completed a market survey and trade study of potential inventory management technologies in partnership with the market research firm, yet2. The products from the MEDIScope effort, including the market survey results, preliminary functional requirements and a concept of operations, have been handed off to a development team at Glenn Research Center (GRC) and ZIN Technologies for technology maturation. In the development phase, the AMIS team will finalize system requirements, down select technologies, integrate with a future exploration Crew Health and Performance Integrated Data Architecture, and conduct design reviews. The project will culminate in an ISS technical flight demonstration in FY27.

MEDIScope↗

NASA NTRS1972

Prospects for low wing-loading STOL transports with ride smoothing.

Airplanes with low wing-loadings provide STOL capability without reliance on auxiliary propulsion or augmented lift, but require a ride smoothing control system to provide acceptable passenger comfort. A parametric study produced a configuration having a .35 thrust-to-weight ratio and a 50 psf wing loading, and which satisfied specified mission requirements and airworthiness standards. A ride-smoothing control system (RCS) synthesis was then performed which consisted of ride quality criteria definition, RCS concept trades, and analysis of RCS performance benefits at significant flight conditions. Within the limitations of the study it is concluded that this is a viable approach to STOL airplane design.

Holloway, R. B.↗

NASA NTRS1991

Technology needs for high-speed rotorcraft

A study to determine the technology development required for high-speed rotorcraft development was conducted. The study begins with an initial assessment of six concepts capable of flight at, or greater than 450 knots with helicopter-like hover efficiency (disk loading less than 50 pfs). These concepts were sized and evaluated based on measures of effectiveness and operational considerations. Additionally, an initial assessment of the impact of technology advances on the vehicles attributes was made. From these initial concepts a tilt wing and rotor/wing concepts were selected for further evaluation. A more detailed examination of conversion and technology trade studies were conducted on these two vehicles, each sized for a different mission.

Rutherford, John↗

NASA NTRS1989

Dual-fuel versus single-fuel propulsion systems for AMLS applications

The results of using a computerized preliminary design system to integrate propulsion systems examined as a part of the Space Transportation Main Engine (STME) and Space Transportation Booster Engine (STBE) studies with reference vehicle concepts from the Advanced Manned Launch System (AMLS) study are presented. The major trade study presented is an analysis of the effect of using a single fuel for both stages of two-stage AMLS reference vehicles as opposed to using a separate fuel for the boosters. Other trade studies presented examine the effect of varying relevant engine parameters in an attempt to optimize the reference engines for use with the AMLS launch vehicles. In each propulsion trade discussed, special attention is given to the major vehicle performance and operational issues involved.

Stanley, Douglas O.↗

NASA NTRS2016

Liquefaction and Storage of In-Situ Oxygen on the Surface of Mars

The In-Situ production of propellants for Martian and Lunar missions has been heavily discussed since the mid 1990's. One portion of the production of the propellants is the liquefaction, storage, and delivery of the propellants to the stage tanks. Two key technology development efforts are required: large refrigeration systems (cryocoolers) to perform the liquefaction and high performance insulation within a soft vacuum environment. Several different concepts of operation may be employed to liquefy the propellants based on how and where these two technologies are implemented. The concepts that were investigated include: using an accumulator tank to store the propellant until it is needed, liquefying in the flow stream going into the tank, and liquefying in the flight propellant tank itself. The different concept of operations were studied to assess the mass and power impacts of each concept. Additionally, the trade between insulation performance and cryocooler mass was performed to give performance targets for soft vacuum insulation development. It was found that liquefying within the flight propellant tank itself adds the least mass and power requirements to the mission.

Cryogenic Fluid Management↗

NASA NTRS2015

Human Research Program Advanced Exercise Concepts (AEC) Overview

Exercise countermeasures provide benefits that are crucial for successful human spaceflight, to mitigate the spaceflight physiological deconditioning which occurs during exposure to microgravity. The NASA Human Research Program (HRP) within the Human Exploration and Operations Mission Directorate (HEOMD) is managing next generation Advanced Exercise Concepts (AEC) requirements development and candidate technology maturation to Technology Readiness Level (TRL) 7 (ground prototyping and flight demonstration) for all exploration mission profiles from Multi Purpose Crew Vehicle (MPCV) Exploration Missions (up to 21 day duration) to Mars Transit (up to 1000 day duration) missions. These validated and optimized exercise countermeasures systems will be provided to the ISS Program and MPCV Program for subsequent flight development and operations. The International Space Station (ISS) currently has three major pieces of operational exercise countermeasures hardware: the Advanced Resistive Exercise Device (ARED), the second-generation (T2) treadmill, and the cycle ergometer with vibration isolation system (CEVIS). This suite of exercise countermeasures hardware serves as a benchmark and is a vast improvement over previous generations of countermeasures hardware, providing both aerobic and resistive exercise for the crew. However, vehicle and resource constraints for future exploration missions beyond low Earth orbit will require that the exercise countermeasures hardware mass, volume, and power be minimized, while preserving the current ISS capabilities or even enhancing these exercise capabilities directed at mission specific physiological functional performance and medical standards requirements. Further, mission-specific considerations such as preservation of sensorimotor function, autonomous and adaptable operation, integration with medical data systems, rehabilitation, and in-flight monitoring and feedback are being developed for integration with the exercise countermeasures systems. Numerous technologies have been considered and evaluated against HRP-approved functional device requirements for these extreme mission profiles, and include wearable sensors, exoskeletons, flywheel, pneumatic, and closed-loop microprocessor controlled motor driven systems. Each technology has unique advantages and disadvantages. The Advanced Exercise Concepts project oversees development of candidate next generation exercise countermeasures hardware, performs trade studies of current and state of the art exercise technologies, manages and supports candidate systems physiological evaluations with human test subjects on the ground, in flight analogs and flight. The near term goal is evaluation of candidate systems in flight, culminating in an integrated candidate next generation exercise countermeasures suite on the ISS which coalesces research findings from HRP disciplines in the areas of exercise performance for muscle, bone, cardiovascular, sensorimotor, behavioral health, and nutrition for optimal benefit to the crew.

Countermeasures↗