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NASA NTRS2016

Orion Versus Poseidon: Understanding How Nasa's Crewed Capsule Survives Nature's Fury

This presentation summarizes the Marshall Space Flight Center Natural Environments Terrestrial and Planetary Environments (TPE) Team support to the NASA Orion space vehicle. The Orion vehicle, part of the Multi-Purpose Crew Vehicle Program, is designed to carry astronauts beyond low-Earth orbit and is currently undergoing a series of tests including Exploration Flight Test (EFT)-1. This design must address the natural environment to which the capsule and launch vehicle are exposed during all mission phases. In addition, the design must, to the best extent possible, implement the same process and data to be utilized on launch day. The TPE utilizes meteorological data to assess the sensitivities of the vehicle due to the terrestrial environment. The presentation describes examples of TPE support for vehicle design and several tests, as well as support for EFT-1 and planning for upcoming Exploration Missions while emphasizing the importance of accounting for the natural environment's impact to the vehicle early in the vehicle's program.

Barbre, Robert E., Jr.↗

NASA NTRS2016

Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

The James Webb Space Telescope (JWST) will likely revolutionize transiting exoplanet atmospheric science, due to a combination of its capability for continuous, long duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) Cycle 1 program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful transiting exoplanet characterization programs in later cycles. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed community targets'') that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations. The latter are a unique challenge compared to transit observations because of their significantly longer durations. Using only a single mode, we propose to observe a full-orbit phase curve of one of the previously characterized, short-orbital-period planets to evaluate the facility-level aspects of long, uninterrupted time-series observations.

JWST Early Release Science (ERS)↗

NASA NTRS2016

Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

The James Webb Space Telescope (JWST) will likely revolutionize transiting exoplanet atmospheric science, due to a combination of its capability for continuous, long duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) Cycle1 program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful transiting exoplanet characterization programs in later cycles. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed community targets) that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWSTs continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring cloudshazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations. The latter are a unique challenge compared to transit observations because of their significantly longer durations. Using only a single mode, we propose to observe a full-orbit phase curve of one of the previously characterized, short-orbital-period planets to evaluate the facility-level aspects of long, uninterrupted time-series observations.

Stevenson, Kevin B.↗

NASA NTRS2018

ORION - Crew Module Side Hatch: Proof Pressure Test Anomaly Investigation

The Orion Multi-Purpose Crew Vehicle program was performing a proof pressure test on an engineering development unit (EDU) of the Orion Crew Module Side Hatch (CMSH) assembly. The purpose of the proof test was to demonstrate structural capability, with margin, at 1.5 times the maximum design pressure, before integrating the CMSH to the Orion Crew Module structural test article for subsequent pressure testing. The pressure test was performed at lower pressures of 3 psig, 10 psig and 15.75 psig with no apparent abnormal behavior or leaking. During pressurization to proof pressure of 23.32 psig, a loud 'pop' was heard at ~21.3 psig. Upon review into the test cell, it was noted that the hatch had prematurely separated from the proof test fixture, thus immediately ending the test. The proof pressure test was expected be a simple verification but has since evolved into a significant joint failure investigation from both Lockheed Martin and NASA.

Evernden, Brent A.↗

NASA NTRS2020

Application of Quasi-Static Modal Analysis to an Orion Multi-Purpose Crew Vehicle Test

Bolted structural joints often exhibit load-dependent stiffness and energy dissipation that leads to nonlinear, amplitude dependent frequency and damping in the structure. As an alternative to direct integration of the nonlinear equations of motion, quasi-static modal analysis (QSMA) determines the dependence of frequency and damping on response amplitude using loading behavior from nonlinear static analyses. QSMA has previously been demonstrated to substantially reduce computational cost and maintain accuracy relative to full nonlinear dynamic simulation. This work explores the applicability of QSMA to a complex, large-scale aerospace structure. QSMA is employed to analyze a nonlinear model of test hardware developed to support the Orion Multi-Purpose Crew Vehicle program, which exhibited nonlinear behavior during dynamic testing at flight-like load levels. In addition to the extraction of amplitude-dependent frequency and damping curves, a Bouc-Wen hysteresis model was used in conjunction with the quasi-static results to develop nonlinear, uncoupled, time-domain modal equations of motion for the structure. Excellent agreement was observed between the reduced and full-order nonlinear models, encouraging future employment of QSMA to support accurate and efficient model reduction of structures with bolted joint nonlinearities.

QSMA↗

NASA NTRS2023

Assessment of Oceanographic Conditions during the North Atlantic EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) Field Campaign

This manuscript presents an overview of NASA’s EXport Processes in the Ocean from Remote Sensing 2021 Field Campaign in the North Atlantic (EXPORTS NA) and provides quantitative and dynamical descriptions of the physical processes modulating water transformations during the study. A major programmatic goal was to conduct the sampling in a Lagrangian mode so that ocean ecological and biogeochemical changes can be observed independent from physical advective processes. To accomplish this goal, EXPORTS NA conducted a multi-ship, multi-asset field sampling program within a retentive, anticyclonic mode water eddy. Beneath depths of ∼100 m, Lagrangian sampling assets remained within the eddy core waters (ECWs) throughout the experiment, demonstrating that the ECWs within the mode water eddy were retentive. However, strong westerly winds from four storm events deepened the mixed layer (ML) of the surface core waters (SCWs) above the eddy’s mode water core by 25-40 m and exchanged some of the SCWs with surface waters outside of the eddy via Ekman transport. Estimates of flushing times ranged from 5-8 days, with surface exchange fractions ranging from 20-75% and were consistent with particle tracking advected by combined geostrophic and Ekman velocities. The relative contributions of horizontal and vertical advection on changes in ECW tracers depended on the horizontal and vertical gradients of that tracer. For example, horizontal advection played a large role in ECW salinity fluxes, while vertical entrainment played a larger role in the fluxes of nutrients into SCW ML. Each storm injected nutrients and low oxygen waters into the ML, after which the surface ocean ecosystem responded by reducing nutrient concentrations and increasing %O2 saturation levels. Overall, ECW values of chlorophyll and POC were the largest at the onset of the field program and decreased throughout the campaign. The analysis presented provides a physical oceanographic context for the many measurements made during the EXPORTS NA field campaign while illustrating the many challenges of conducting a production-flux experiment, even in a Lagrangian frame, and the inherent uncertainties of interpreting biological carbon pump observations that were collected in a Eulerian frame of reference.

oceanography↗

NASA NTRS2017

Development of NASA Standards for Enabling Certification of Additively Manufactured Parts

There are currently no NASA standards providing specific design and construction requirements for certification of additively manufactured parts. Several international standards organizations are developing standards for additive manufacturing; however, NASA mission schedules preclude the Agency from relying on these organizations to develop standards that are both timely and applicable. NASA and its partners in human spaceflight (Commercial Crew, Space Launch System, and Orion Multi-Purpose Crew Vehicle Programs) are actively developing additively manufactured parts for flight as early as 2018. To bridge this gap, NASA Marshall Space Flight Center (MSFC) is authoring a Center-level standard (MSFC-STD-3716) 1 to establish standard practices for the Laser Powder Bed Fusion (L-PBF) process. In its draft form, the MSFC standard has been used as a basis for L-PBF process implementation for each of the human spaceflight programs. The development of an Agency-level standard is proposed, based upon the principles of MSFC-STD-3716, which would have application to multiple additive manufacturing processes and be readily adaptable to all NASA programs.

NASA Standards↗

NASA NTRS2011

The Effects of Microgravity on Seated Height (Spinal Elongation)

ABSTRACT Many physiological factors, such as spinal elongation, fluid shifts, bone atrophy, and muscle loss, occur during an exposure to a microgravity environment. Spinal elongation is just one of the factors that can also affect the safety and performance of a crewmember while in space. Spinal elongation occurs due to the lack of gravity/compression on the spinal column. This allows for the straightening of the natural spinal curve. There is a possible fluid shift in the inter-vertebral disks that may also result in changes in height. This study aims at collecting the overall change in seated height for crewmembers exposed to a microgravity environment. During previous Programs, Apollo-Soyuz Test Project (ASTP) and Skylab, spinal elongation data was collected from a small number of subjects in a standing posture but were limited in scope. Data from these studies indicated a quick increase in stature during the first few days of weightlessness, after which stature growth reached a plateau resulting in up to a 3% increase of the original measurement [1-5]. However, this data was collected only for crewmembers in standing posture and not in a seated posture. Seated height may have a different effect than standing height due to a change in posture as well as due to a compounded effect of wearing restraints and a potential compression of the gluteal area. Seated height was deemed as a critical measurement in the design of the Constellation Program s (CxP) Crew Exploration Vehicle (CEV), called Orion which is now the point-of-departure vehicle for the Multi-Purpose Crew Vehicle (MPCV) Program; therefore a better understanding of the effects of microgravity on seated height is necessary. Potential changes in seated height that may not have impacted crew accommodation in previous Programs will have significant effects on crew accommodation due to the layout of seats in the Orion.. The current and existing configuration is such that the four crewmembers are stacked two by two with the commander and pilot seats on the top and the two remaining seats underneath, thereby limiting the amount of clearance for the crewmembers seated in the bottom seat. The inner mold line of these types of vehicles are fixed due to other design constraints; therefore, it is essential that all seats incorporate additional clearance to account for adequate spinal growth thereby ensuring that the crew can safely ingress the seat and be strapped in prior to its return to earth. If there is not enough clearance to account for spinal growth deltas between seats then there is the potential that crewmembers will not be able to comfortably and safely fit into their seats. The crewmember in the bottom stacked seat may even have negative clearance with the seat above him or her which could lead to potential ingress/egress issues or potentially injury of the crewmember during landing. These impacts are specific to these types of vehicles with stacked seat configuration. Without proper knowledge of the amount of spinal elongation, or growth, which occurs due to microgravity and space flight, the design of future vehicle(s) or suits may cause injury, discomfort, and limit crew accommodation and crew complements. The experiment primarily aimed to collect seated height data for subjects exposed to microgravity environments, and feed new information regarding the effect of elongation of the spine forward into the design of the Orion. The data collected during the experiment included, two seated height measurement and two digital pictures of seated height pre-, in-, and post-flight. In addition to seated height, crewmembers had an optional task of collecting stature , standing height. Seated height data was obtained from 29 crewmembers that included 8 ISS increment crew (2 females and 6 males) and 21 Shuttle crew (1 female, 20 males), and whose mean age was 48 years ( 4 years). This study utilized the last six Shuttle flights, STS-128 to STS-134. The results show that partipating crewmembers experienced growth up to 6% in seated height and up to 3% in stature. Based on the worst case statistical analysis of the subject data, the recommended seated height growth of 6% will be provided to the designers as the necessary seated height adjustment.

Young, K. S.↗

NASA NTRS1999

MLP: A Parallel Programming Alternative to MPI for New Shared Memory Parallel Systems

Recent developments at the NASA AMES Research Center's NAS Division have demonstrated that the new generation of NUMA based Symmetric Multi-Processing systems (SMPs), such as the Silicon Graphics Origin 2000, can successfully execute legacy vector oriented CFD production codes at sustained rates far exceeding processing rates possible on dedicated 16 CPU Cray C90 systems. This high level of performance is achieved via shared memory based Multi-Level Parallelism (MLP). This programming approach, developed at NAS and outlined below, is distinct from the message passing paradigm of MPI. It offers parallelism at both the fine and coarse grained level, with communication latencies that are approximately 50-100 times lower than typical MPI implementations on the same platform. Such latency reductions offer the promise of performance scaling to very large CPU counts. The method draws on, but is also distinct from, the newly defined OpenMP specification, which uses compiler directives to support a limited subset of multi-level parallel operations. The NAS MLP method is general, and applicable to a large class of NASA CFD codes.

Taft, James R.↗

NASA NTRS2012

Principles to Products: Toward Realizing MOS 2.0

This is a report on the Operations Revitalization Initiative, part of the ongoing NASA-funded Advanced Multi-Mission Operations Systems (AMMOS) program. We are implementing products that significantly improve efficiency and effectiveness of Mission Operations Systems (MOS) for deep-space missions. We take a multi-mission approach, in keeping with our organization's charter to "provide multi-mission tools and services that enable mission customers to operate at a lower total cost to NASA." Focusing first on architectural fundamentals of the MOS, we review the effort's progress. In particular, we note the use of stakeholder interactions and consideration of past lessons learned to motivate a set of Principles that guide the evolution of the AMMOS. Thus guided, we have created essential patterns and connections (detailed in companion papers) that are explicitly modeled and support elaboration at multiple levels of detail (system, sub-system, element...) throughout a MOS. This architecture is realized in design and implementation products that provide lifecycle support to a Mission at the system and subsystem level. The products include adaptable multi-mission engineering documentation that describes essentials such as operational concepts and scenarios, requirements, interfaces and agreements, information models, and mission operations processes. Because we have adopted a model-based system engineering method, these documents and their contents are meaningfully related to one another and to the system model. This means they are both more rigorous and reusable (from mission to mission) than standard system engineering products. The use of models also enables detailed, early (e.g., formulation phase) insight into the impact of changes (e.g., to interfaces or to software) that is rigorous and complete, allowing better decisions on cost or technical trades. Finally, our work provides clear and rigorous specification of operations needs to software developers, further enabling significant gains in productivity.

AMMOS↗

NASA NTRS1974

Thermal stress analysis of reusable surface insulation for shuttle

An iterative procedure for accurately determining tile stresses associated with static mechanical and thermally induced internal loads is presented. The necessary conditions for convergence of the method are derived. An user-oriented computer program based upon the present method of analysis was developed. The program is capable of analyzing multi-tiled panels and determining the associated stresses. Typical numerical results from this computer program are presented.

Ojalvo, I. U.↗

NASA NTRS1977

Multi-anode microchannel arrays

A development program is currently being undertaken to produce photon-counting detector arrays which are suitable for use in both ground-based and space-borne instruments and which utilize the full sensitivity, dynamic range and photometric stability of the microchannel array plate (MCP). The construction of the detector arrays and the status of the development program are described.

Timothy, J. G.↗

NASA NTRS1978

A progress report on multi-anode microchannel arrays

Timothy, J. G.↗

NASA NTRS1992

An interactive multi-block grid generation system

A grid generation procedure combining interactive and batch grid generation programs was put together to generate multi-block grids for complex aircraft configurations. The interactive section provides the tools for 3D geometry manipulation, surface grid extraction, boundary domain construction for 3D volume grid generation, and block-block relationships and boundary conditions for flow solvers. The procedure improves the flexibility and quality of grid generation to meet the design/analysis requirements.

Kao, T. J.↗

NASA NTRS1992

Second NASA Advanced Composites Technology Conference

The conference papers are presented. The Advanced Composite Technology (ACT) Program is a major multi-year research initiative to achieve a national goal of technology readiness before the end of the decade. Conference papers recorded results of research in the ACT Program in the specific areas of automated fiber placement, resin transfer molding, textile preforms, and stitching as these processes influence design, performance, and cost of composites in aircraft structures. These papers will also be included in the Ninth Conference Proceedings to be published by the Federal Aviation Administration as a separate document.

John G Davis, Jr.↗

NASA NTRS1993

Third NASA Advanced Composites Technology Conference, volume 1, part 2

This document is a compilation of papers presented at the Third NASA Advanced Composites Technology (ACT) Conference held at Long Beach, California, 8-11 June 1992. The ACT Program is a major multi-year research initiative to achieve a national goal of technology readiness before the end of the decade. Conference papers recorded results of research in the ACT Program in the specific areas of automated fiber placement, resin transfer molding, textile preforms, and stitching as these processes influence design, performance, and cost of composites in aircraft structures. Papers sponsored by the Department of Defense on the Design and Manufacturing of Low Cost Composites (DMLCC) are also included in Volume 2 of this document.

Davis, John G., Jr.↗

NASA NTRS1993

Third NASA Advanced Composites Technology Conference, volume 1, part 1

This document is a compilation of papers presented at the Third NASA Advanced Composites Technology (ACT) Conference. The ACT Program is a major multi-year research initiative to achieve a national goal of technology readiness before the end of the decade. Conference papers recorded results of research in the ACT Program in the specific areas of automated fiber placement, resin transfer molding, textile preforms, and stitching as these processes influence design, performance, and cost of composites in aircraft structures. Papers sponsored by the Department of Defense on the Design and Manufacturing of Low Cost Composites (DMLCC) are also included in Volume 2 of this document.

Davis, John G., Jr.↗

NASA NTRS2020

Small Business Launches Down-to-Earth Products via NASA SBIR Program

Through the SBIR program, DSSP developed a multi-pulse solid rocket motor for NASA that will enable stabilized interplanetary flight for small satellites. Another of DSSP’s core innovations with roots in the SBIR program is already having an even greater impact. Originally proposed to fuel a microsatellite thruster for Earth-observation missions, DSSP’s HAN-based green electric monopropellants (GEM and AF-M315E) technology is powering larger satellites, enhancing downhole oil and gas recovery, and much more. Highly insensitive to ignition by spark, flame, or shock, GEM-based innovations are stable, non-toxic, and more controllable than conventional propellants.

Bruce R Cogan↗