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NASA NTRS2010

Lessons Learned in Building the Ares Projects

Since being established in 2005, the Ares Projects at Marshall Space Flight Center have been making steady progress designing, building, testing, and flying the next generation of exploration launch vehicles. Ares is committed to rebuilding crucial capabilities from the Apollo era that made the first human flights to the Moon possible, as well as incorporating the latest in computer technology and changes in management philosophy. One example of an Apollo-era practice has been giving NASA overall authority over vehicle integration activities, giving civil service engineers hands-on experience in developing rocket hardware. This knowledge and experience help make the agency a "smart buyer" of products and services. More modern practices have been added to the management tool belt to improve efficiency, cost effectiveness, and institutional knowledge, including knowledge management/capture to gain better insight into design and decision making; earned value management, where Ares won a NASA award for its practice and implementation; designing for operability; and Lean Six Sigma applications to identify and eliminate wasted time and effort. While it is important to learn technical lessons like how to fly and control unique rockets like the Ares I-X flight test vehicle, the Ares management team also has been learning important lessons about how to manage large, long-term projects.

Sumrall, John Phil↗

NASA NTRSDate not supplied

SpaceX Dragon Spacecraft Post Flight MMOD Inspection Campaign

The SpaceX Dragon spacecraft performed 20 resupply flights to the International Space Station (ISS) between 2012 and 2020. After each mission, a team led by the NASA Johnson Space Center Hypervelocity Impact Technology (HVIT) Group inspected each Dragon vehicle exterior for hypervelocity impact damage. A general description of the inspected vehicle areas is provided as well as mission details such as exposure duration and launch dates. This paper documents the general inspection procedure for collection of data and the post inspection data analysis process. It also provides details of the observation data collected in addition to the spectroscopic analysis results of intact samples collected to discern the source of the impacting particle. A comparison between observed impacts and the expected number of damage features calculated by Bumper 3 with the latest micrometeoroid and orbital debris (MMOD) environments are also presented. Statistics on the >300 impact features documented in the database will provide insight into the depth to diameter ratios and other relationships. The quality of the comparison between the observations and code predictions are dependent on several factors. The paper provides details of each of these variables.

orbital debris↗

NASA NTRS2005

Final Report for the Development of the NASA Technical Report Server (NTRS)

The author performed a variety of research, development and consulting tasks for NASA Langley Research Center in the area of digital libraries (DLs) and supporting technologies, such as the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). In particular, the development focused on the NASA Technical Report Server (NTRS) and its transition from a distributed searching model to one that uses the OAI-PMH. The Open Archives Initiative (OAI) is an international consortium focused on furthering the interoperability of DLs through the use of "metadata harvesting". The OAI-PMH version of NTRS went into public production on April 28, 2003. Since that time, it has been extremely well received. In addition to providing the NTRS user community with a higher level of service than the previous, distributed searching version of NTRS, it has provided more insight into how the user community uses NTRS in a variety of deployment scenarios. This report details the design, implementation and maintenance of the NTRS. Source code is included in the appendices.

Nelson, Michael L.↗

NASA NTRS2014

NASA's Optical Measurement Program 2014

The Optical Measurements Group (OMG) within the NASA Orbital Debris Program Office (ODPO) addresses U.S. National Space Policy goals by monitoring and characterizing debris. Since 2001, the OMG has used the Michigan Orbital Debris Survey Telescope (MODEST) at Cerro Tololo Inter-American Observatory (CTIO) in Chile for general orbital debris surveys. The 0.6-m Schmidt MODEST provides calibrated astronomical data of GEO targets, both catalogued and uncatalogued debris, with excellent image quality. The data are utilized by the ODPO modeling group and are included in the Orbital Debris Engineering Model (ORDEM) v. 3.0. MODEST and the CTIO/SMARTS (Small and Moderate Aperture Research Telescope System) 0.9 m are both employed to acquire filter photometry data as well as synchronously observe targets in selected optical filters. Obtaining data synchronously yields data for material composition studies as well as longer orbital arc data on the same target without time delay or bias from a rotating, tumbling, or spinning target. Observations of GEO orbital debris using the twin 6.5-m Magellan telescopes at Las Campanas Observatory in Chile for deep imaging (Baade) and spectroscopic data (Clay) began in 2011. Through the data acquired on Baade, debris has been detected that reaches approx. 3 magnitudes fainter than detections with MODEST, while the spectral data from Clay provide better resolved information used in material characterization analyses. To better characterize and model optical data, the Optical Measurements Center (OMC) at NASA/JSC has been in operation since 2005, resulting in a database of comparison laboratory data. The OMC is designed to emulate illumination conditions in space using equipment and techniques that parallel telescopic observations and sourcetarget- sensor orientations. Lastly, the OMG is building the Meter Class Autonomous Telescope (MCAT) at Ascension Island. The 1.3-m telescope is designed to observe GEO and LEO targets, using a modified Ritchey-Chrétien configuration on a double horseshoe equatorial mount to allow tracking objects at LEO rates through the dome's keyhole at zenith. Through the data collection techniques employed at these unique facilities, NASA's ODPO has developed a multifaceted approach to characterize the orbital debris risk to satellites in various altitudes and provide insight leading toward material characterization of debris via photometric and spectroscopic measurements. Ultimately, the data are used in conjunction with in-situ and radar measurements to provide accurate data for models of our space environment and for facilitating spacecraft risk assessment.

Cowardin, H.↗

NASA NTRS1999

Circadian and sleep-dependent regulation of hormone release in humans

Daily oscillations characterize the release of nearly every hormone. The circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, generates circadian, approximately 24-hour rhythms in many physiologic functions. However, the observed hormonal oscillations do not simply reflect the output of this internal clock. Instead, daily hormonal profiles are the product of a complex interaction between the output of the circadian pacemaker, periodic changes in behavior, light exposure, neuroendocrine feedback mechanisms, gender, age, and the timing of sleep and wakefulness. The interaction of these factors can affect hormonal secretory pulse frequency and amplitude, with each endocrine system differentially affected by these factors. This chapter examines recent advances in understanding the effects on endocrine rhythms of a number of these factors. Sleep exerts a profound effect on endocrine secretion. Sleep is a dynamic process that is characterized by periodic changes in electrophysiologic activity. These electrophysiologic changes, which are used to mark the state and depth of sleep, are associated with periodic, short-term variations in hormonal levels. The secretion of hormones such as renin and human growth hormone are strongly influenced by sleep or wake state, while melatonin and cortisol levels are relatively unaffected by sleep or wake state. In addition, sleep is associated with changes in posture, behavior, and light exposure, each of which is known to affect endocrine secretion. Furthermore, the tight concordance of habitual sleep and wake times with certain circadian phases has made it difficult to distinguish sleep and circadian effects on these hormones. Specific protocols, designed to extract circadian and sleep information semi-independently, have been developed and have yielded important insights into the effects of these regulatory processes. These results may help to account for changes in endocrine rhythms observed in circadian rhythm sleep disorders, including the dyssomnia of shift work and visual impairment. Yet to be fully investigated are the interactions of these factors with age and gender. Characterization of the factors governing hormone secretion is critical to understanding the temporal regulation of endocrine systems and presents many exciting areas for future research.

Non-NASA Center↗

NASA NTRS1998

New Doppler echocardiographic applications for the study of diastolic function

Doppler echocardiography is one of the most useful clinical tools for the assessment of left ventricular (LV) diastolic function. Doppler indices of LV filling and pulmonary venous (PV) flow are used not only for diagnostic purposes but also for establishing prognosis and evaluating the effect of therapeutic interventions. The utility of these indices is limited, however, by the confounding effects of different physiologic variables such as LV relaxation, compliance and filling pressure. Since alterations in these variables result in changes in Doppler indices of opposite direction, it is often difficult to determine the status of a given variable when a specific Doppler filling pattern is observed. Recently, color M-mode and tissue Doppler have provided useful insights in the study of diastolic function. These new Doppler applications have been shown to provide an accurate estimate of LV relaxation and appear to be relatively insensitive to the effects of preload compensation. This review will focus on the complementary role of color M-mode and tissue Doppler echocardiography and traditional Doppler indices of LV filling and PV flow in the assessment of diastolic function.

NASA Discipline Cardiopulmonary↗

NASA NTRS2011

Lessons Learned in Engineering

This Contractor Report (CR) is a compilation of Lessons Learned in approximately 55 years of engineering experience by each James C. Blair, Robert S. Ryan, and Luke A. Schutzenhofer. The lessons are the basis of a course on Lessons Learned that has been taught at Marshall Space Flight Center. The lessons are drawn from NASA space projects and are characterized in terms of generic lessons learned from the project experience, which are further distilled into overarching principles that can be applied to future projects. Included are discussions of the overarching principles followed by a listing of the lessons associated with that principle. The lesson with sub-lessons are stated along with a listing of the project problems the lesson is drawn from, then each problem is illustrated and discussed, with conclusions drawn in terms of Lessons Learned. The purpose of this CR is to provide principles learned from past aerospace experience to help achieve greater success in future programs, and identify application of these principles to space systems design. The problems experienced provide insight into the engineering process and are examples of the subtleties one experiences performing engineering design, manufacturing, and operations.

Blair, J. C.↗

NASA NTRS2011

Lessons Learned in Engineering

Blair, James C.↗

NASA NTRS2019

James Webb Space Telescope Optical Telescope Element / Integrated Science Instrument Module (OTIS) Cryogenic Vacuum Test Part I: Thermal Architecture

The James Webb Space Telescope (JWST), set to launch in early 2019, is currently undergoing a series of system-level environmental tests to verify its workmanship and end-to-end functionality. As part of this series, the Optical Telescope Element and Integrated Science Instrument Module (OTIS) Cryo-Vacuum (CV) test, the most complex cryogenic test executed to date by NASA, was completed in 2017 at the Johnson Space Center's Chamber A facility. The OTIS CV test was intended as a comprehensive test of the integrated instrument and telescope systems to fully understand its optical, structural, and thermal performance within its intended flight environment. Due to its complexity, extensive pre-test planning was required to ensure payload safety and compliance with all limits and constraints. A comprehensive thermal analysis campaign was undertaken to predict the behavior of the test payload during its transition to cryogenic temperatures and back to ambient, and exhaustive preparations for off-nominal scenarios were studied due to the increased possibility of unanticipated events during the 100-day test length. This current four-part online course for the NASA Engineering and Safety Center (NESC) Academy gives a thorough overview of the mutiple years of preparation executed by hundreds of individuals to ensure the success of the JWST OTIS CV Test. Part I will introduce the major components of James Webb and specifically the OTIS CV Test thermal architecture. Part II will encompass the extensive thermal analysis performed to prepare for the test. Part III will talk about the preparations for off-nominal events: what analysis was done, and how steps were taken pre-test to anticipate unexpected circumstances and mitigate their impacts to hardware and test timeline. Part IV is a recap of the lessons learned from the thermal perspective for both the payload and ground support equipment (GSE) test conductors. It is hoped that the insight gained from the OTIS CV test campaign will benefit planning and execution for upcoming large cryogenic missions.

OTIS↗

NASA NTRS2019

James Webb Space Telescope Optical Telescope Element / Integrated Science Instrument Module (OTIS) Cryogenic Vacuum Test Part II: Thermal Analysis

The James Webb Space Telescope (JWST), set to launch in early 2019, is currently undergoing a series of system-level environmental tests to verify its workmanship and end-to-end functionality. As part of this series, the Optical Telescope Element and Integrated Science Instrument Module (OTIS) Cryo-Vacuum (CV) test, the most complex cryogenic test executed to date by NASA, was completed in 2017 at the Johnson Space Center's Chamber A facility. The OTIS CV test was intended as a comprehensive test of the integrated instrument and telescope systems to fully understand its optical, structural, and thermal performance within its intended flight environment. Due to its complexity, extensive pre-test planning was required to ensure payload safety and compliance with all limits and constraints. A comprehensive thermal analysis campaign was undertaken to predict the behavior of the test payload during its transition to cryogenic temperatures and back to ambient, and exhaustive preparations for off-nominal scenarios were studied due to the increased possibility of unanticipated events during the 100-day test length. This current four-part online course for the NASA Engineering and Safety Center (NESC) Academy gives a thorough overview of the multiple years of preparation executed by hundreds of individuals to ensure the success of the JWST OTIS CV Test. Part I will introduce the major components of James Webb and specifically the OTIS CV Test thermal architecture. Part II will encompass the extensive thermal analysis performed to prepare for the test. Part III will talk about the preparations for off-nominal events: what analysis was done, and how steps were taken pre-test to anticipate unexpected circumstances and mitigate their impacts to hardware and test timeline. Part IV is a recap of the lessons learned from the thermal perspective for both the payload and ground support equipment (GSE) test conductors. It is hoped that the insight gained from the OTIS CV test campaign will benefit planning and execution for upcoming large cryogenic missions.

Testing↗

NASA NTRS1995

Experimental Results on the Feasibility of an Aerospike for Hypersonic Missiles

A series of wind tunnel tests have been performed on an aerospike-protected missile dome at a Mach number of 6 to obtain quantitative surface pressure and temperature-rise data, as well as qualitative flow visualization data. These data were used to determine aerospike concept feasibility and will also provide a database to be used for calibration of computational fluid dynamics codes. Data were obtained on the hemispherical missile dome with and without an aerospike that protrudes ahead of the dome along the axisymmetric center line. Data were obtained on two models (one pressure, one temperature) in the NASA Langley 20-Inch Mach 6 Tunnel at a freestream Reynolds number of 8.0 x 10(exp 6) per feet and angles of attack from 0 to 40 degrees. Surface pressure and temperature-rise results indicate that the aerospike is effective for very low angles of attack (less than 5 degrees) at Mach 6. Above 5 degrees, impingement of the aerospike bow shock and the flow separation shock from the recirculation region created by the aerospike causes pressure and temperature increases on the windward side of the dome which exceed values observed in the same region with the aerospike removed. Flow characterization obtained via oil-flow and schlieren photographs provides some insight into the quantitative surface data results, including vortical flow and shock-wave impingement.

Huebner, Lawrence D.↗

NASA NTRS2012

Interpretation of Vector Electric Field Measurements of Bursty Langmuir Waves in the Cusp

An analysis of auroral Langmuir waves in the cusp observed by two high-frequency electric field instruments on the TRICE high-flyer sounding rocket shows many examples of Langmuir wave bursts modulated at approximately 10 kHz. Previous studies have explained these and similar observations as the result of beating between waves with very close frequencies near the Langmuir cutoff, resulting from either wave-wave interactions or independent linear excitations. The unique three-dimensional (3-D) data set provided by the NASA Goddard Space Flight Center TAEFWD instrument shows that up to 25% of waveforms selected from the most intense bursts exhibit anisotropic modulations, i.e., the beat nulls and peaks are not aligned in time across the three perpendicular electric field components. Modulations of this type arise when superposed wave normal modes possess differing polarizations, and simulations using wave modes calculated with the J-WHAMP numerical dispersion code show (1) that waves with differing polarizations can exist in conditions like those observed by TRICE-High and (2) that superpositions of such waves can produce anisotropic modulation. Fourier analysis of the 3-D waveform data suggests that both linear and elliptically polarized waves are present near the Langmuir cutoff at these times. These observations illustrate how 3-D measurements can give valuable insight into the nature of wave interactions in the auroral plasma environment.

Dombrowski, M. P.↗

NASA NTRSDate not supplied

Wi-Fi Signal Survey of the International Space Station by Autonomous Free-Flying Robot

This paper analyzes Wi-Fi signal propagation inside pressurized modules of the International Space Station (ISS). Various flight datasets were collected by the Astrobee fleet of autonomous free-flying robots developed by the NASA Ames Research Center (ARC). The enclosed module spaces of the ISS pose unique challenges for Wi-Fi signal propagation, and understanding these challenges is crucial for optimizing connectivity in such environments. The survey data presented are valuable for optimizing wireless access point (WAP) locations and conditions. A computational method is developed to analyze the wireless communication system, RF coverage, and module compositions. The method is both rigorous and practical for assessing the ISS wireless system performance. The computational tools in this paper serve as a complementary approach to direct, on-orbit measurements, which is a complicated and expensive task. In some operational scenarios, ground measurements may be intractable due to the size of the spacecraft. Results from this research will aid future space missions and commercial spacecraft, providing insights into optimal WAP placements and robust wireless communication systems.

Astrobee↗

NASA NTRSDate not supplied

Wi-Fi Signal Survey of the International Space Station by Autonomous Free-Flying Robot

International Space Station↗

NASA NTRS1998

High Speed Research: Propulsion Project Accomplishments

This past year has been one of great accomplishment for the propulsion element of NASA's High Speed Research (HSR) Program. The HSR Program is a NASA/industry partnership to develop the high-risk/high-payoff airframe and propulsion technologies applicable to a second-generation supersonic commercial transport, or High Speed Civil Transport (HSCT). The propulsion element, which also involves industry partners, is managed by the NASA Lewis Research Center. These technologies will contribute greatly to U.S. industry's ability to make an informed product launch decision for an HSCT vehicle. Specific NASA Lewis accomplishments in 1997 include: 1. Small-scale combustor sector tests conducted in Lewis' Engine Research Building contributed to the evolution of approaches to developing a combustor with ultralow NOx emissions. 2. Components were tested in Lewis' CE-9 facility (in Lewis' Engine Research Building) to assess the performance of candidate ceramic matrix composite (CMC) materials in this realistic combustion environment. Test results were promising, and acceptable levels of structural durability were demonstrated for the ceramic matrix composite material tested. Ceramic matrix composites continue to show great promise for use in HSCT combustor liners. 3. Engine emissions tests in Lewis' Propulsion Systems Laboratory provided insight into other classes of emissions (e.g., particulates and aerosols) which will be important to control in HSCT propulsion system designs. 4. Small-scale nozzle tests conducted in Lewis' Aero-Acoustic Propulsion Laboratory are contributing to the design of a low-noise, high-performance mixer/ejector nozzle configuration for HSCT engines. Over 18,000 hours of durability testing were completed in Lewis' materials laboratories to evaluate superalloy and g-titanium aluminide performance for HSCT nozzle applications. A two-dimensional supersonic inlet concept was tested in Lewis' 10- by 10-Foot Supersonic Wind Tunnel. The extensive database and the knowledge gained contributed to the selection of a two-dimensional inlet as the preferred inlet concept for the HSR Program.

Shaw, Robert J.↗

NASA NTRS2018

Development and Testing of a Vehicle Management System for Autonomous Spacecraft Habitat Operations

As the increased distance between Earth-based mission control and the spacecraft results in increasing communication delays, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions. In addition, both near-term and future missions will feature significant periods when crew is not present, meaning the vehicles will need to operate themselves autonomously. NASA's Advanced Exploration Systems Program pioneers new approaches for rapidly developing prototype systems, demonstrating key capabilities, and validating operational concepts for future human missions beyond low-Earth orbit. Under this program, NASA has developed and demonstrated multiple technologies to enable the autonomous operation of a dormant space habitat. These technologies included a fault-tolerant avionics architecture, novel spacecraft power system and power system controller, and autonomy software to control the habitat. The demonstration involved simulation of the habitat and multiple spacecraft sub-systems (power storage and distribution, avionics, and air-side life-support) during a multi-day test at NASA's Johnson Space Center. The foundation of the demonstration was â€˜quiescent operations' of a habitat during a 55 minute eclipse period. For this demonstration, the spacecraft power distribution system and air-side life support system were simulated at a high level of fidelity; additional systems were managed, but with lower fidelity operational constraints and system behavior. Operational constraints for real and simulated loads were developed by analyzing on-orbit hardware and evaluating future Exploration capable technology. A total of 13 real and simulated loads were used during the test. Eight scenarios including both nominal and off-nominal conditions were performed. Over the course of the test, every application performed its desired functions successfully during the simulated tests. The results will inform both future tests, as well as provide insight to NASA's domestic and international partners, as they construct the next generation of space habitats to be used on beyond-Earth missions.

Autonomous Systems and Operations↗

NASA NTRS1999

Non-Intrusive Laser-Induced Imaging for Speciation and Patternation in High Pressure Gas Turbine Combustors

The next generation of was turbine combustors for aerospace applications will be required to meet increasingly stringent constraints on fuel efficiency, noise abatement, and emissions. The power plants being designed to meet these constraints will operate at extreme conditions of temperature and pressure, thereby generating unique challenges to the previously employed diagnostic methodologies. Current efforts at NASA Glenn Research Center (GRC) utilize optically accessible, high pressure flametubes and sector combustor rigs to probe, via advanced nonintrusive laser techniques, the complex flowfields encountered in advanced combustor designs. The fuel-air mixing process is of particular concern for lowering NO(x) emissions generated in lean, premixed engine concepts. Using planar laser-induced fluorescence (PLIF) we have obtained real-time, detailed imaging of the fuel spray distribution for a number of fuel injector over a wide range of operational conditions that closely match those expected in the proposed propulsion systems. Using a novel combination of planar imaging, of fuel fluorescence and computational analysis that allows an examination of the flowfield from any perspective, we have produced spatially and temporally resolved fuel-air distribution maps. These maps provide detailed insight into the fuel injection at actual conditions never before possible, thereby greatly enhancing the evaluation of fuel injector performance and combustion phenomena.

Locke, Randy J.↗

NASA NTRS2008

Engine Validation of Noise and Emission Reduction Technology Phase I

This final report has been prepared by Honeywell Aerospace, Phoenix, Arizona, a unit of Honeywell International, Inc., documenting work performed during the period December 2004 through August 2007 for the NASA Glenn Research Center, Cleveland, Ohio, under the Revolutionary Aero-Space Engine Research (RASER) Program, Contract No. NAS3-01136, Task Order 8, Engine Validation of Noise and Emission Reduction Technology Phase I. The NASA Task Manager was Dr. Joe Grady of the NASA Glenn Research Center. The NASA Contract Officer was Mr. Albert Spence of the NASA Glenn Research Center. This report is for a test program in which NASA funded engine validations of integrated technologies that reduce aircraft engine noise. These technologies address the reduction of engine fan and jet noise, and noise associated with propulsion/airframe integration. The results of these tests will be used by NASA to identify the engineering tradeoffs associated with the technologies that are needed to enable advanced engine systems to meet stringent goals for the reduction of noise. The objectives of this program are to (1) conduct system engineering and integration efforts to define the engine test-bed configuration; (2) develop selected noise reduction technologies to a technical maturity sufficient to enable engine testing and validation of those technologies in the FY06-07 time frame; (3) conduct engine tests designed to gain insight into the sources, mechanisms and characteristics of noise in the engines; and (4) establish baseline engine noise measurements for subsequent use in the evaluation of noise reduction.

Weir, Don↗