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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Experimental Study of the Stability of Aircraft Fuels at Elevated Temperatures

An experimental study of fuel stability was conducted in an apparatus which simulated an aircraft gas turbine fuel system. Two fuels were tested: Jet A and Number 2 Home Heating oil. Jet A is an aircraft gas turbine fuel currently in wide use. No. 2HH was selected to represent the properties of future turbine fuels, particularly experimental Reference Broad Specification, which, under NASA sponsorship, was considered as a possible next-generation fuel. Tests were conducted with varying fuel flow rates, delivery pressures and fuel pretreatments (including preheating and deoxygenation). Simulator wall temperatures were varied between 422K and 672K at fuel flows of 0.022 to 0.22 Kg/sec. Coking rate was determined at four equally-spaced locations along the length of the simulator. Fuel samples were collected for infrared analysis. The dependence of coking rate in Jet A may be correlated with surface temperature via an activation energy of 9 to 10 kcal/mole, although the results indicate that both bulk fluid and surface temperature affect the rate of decomposition. As a consequence, flow rate, which controls bulk temperature, must also be considered. Taken together, these results suggest that the decomposition reactions are initiated on the surface and continue in the bulk fluid. The coking rate data for No. 2 HH oil are very highly temperature dependent above approximately 533K. This suggests that bulk phase reactions can become controlling in the formation of coke.

Vranos, A.↗
NASA NTRS2006

Automated Derivation of Complex System Constraints from User Requirements

International Space Station (ISS) payload developers submit their payload science requirements for the development of on-board execution timelines. The ISS systems required to execute the payload science operations must be represented as constraints for the execution timeline. Payload developers use a software application, User Requirements Collection (URC), to submit their requirements by selecting a simplified representation of ISS system constraints. To fully represent the complex ISS systems, the constraints require a level of detail that is beyond the insight of the payload developer. To provide the complex representation of the ISS system constraints, HOSC operations personnel, specifically the Payload Activity Requirements Coordinators (PARC), manually translate the payload developers simplified constraints into detailed ISS system constraints used for scheduling the payload activities in the Consolidated Planning System (CPS). This paper describes the implementation for a software application, User Requirements Integration (URI), developed to automate the manual ISS constraint translation process.

Muery, Kim↗
NASA NTRSDate not supplied

Enabling Mission Flexibility to Battery Driven Deep Space Endeavors With Generalized Battery-Health-Monitoring Using Physics-Based and Data-Driven Reduced-Order Models

The needs and requirements for an electrochemical energy storage for deep space exploration is well explored. It is often understood that different mission sites and environmental conditions require different battery chemistries or technologies. Additionally, various engineering solutions are deployed to overcome specific chemical challenges. One often overlooked need is the “health” monitoring of an electrochemical storage system. The term generalized health monitoring, as envisioned in this work, refers to the monitoring of various aspects such as electrode health, electrolyte health, reaction pathway health, cooling system health, sensor health, and BMS health [1]. Generalized health monitoring allows mission leads, engineers, and scientists to incorporate flexibility in mission designs, make on-the-fly mission changes, and extend the duration of science missions. Moreover, it enables automation and data-driven decision-making without compromising safety and performance. Recently, our group developed a hierarchy of thermal reduced-order models (TROM) by combining a physics-based modeling approach and data-driven model reduction techniques applied to flight data [2]. The resulting TROMs were found to be not only accurate but also identifiable from the flight data. Consequently, the coefficient of variance of the model parameters is small over the course of hundreds of flights, allowing for monitoring the parameter evolution trajectories as the battery ages and degrades. These parameters constitute the metrics of the generalized health of a battery. Monitoring their evolution allows such models to be used for anomaly detection and prognostics, improving early detection of abnormal behavior and thus enabling timely maintenance, longer battery life, and enhanced battery safety. For this presentation, the practicality of the thermal model will be validated on a pack of 14cells under various topology configurations such as 1S14P, 2P7S, 7S2P, and 1P14S. It is well known that manufacturing and non-uniform aging lead to variability in the performance of a cell, which is exacerbated by cell balancing during active load. Additionally, in extreme scenarios, the paramount objective is to complete the mission, regardless of the stresses on the battery. Topology-induced balancing issues further stress the battery. The goal of this study is to determine if the noise (identifiability) in the reduced-order thermal model parameters is sensitive to topology, cell spacing, cooling strategy, and manufacturing or age variability. The variability in cells is considered by assuming a multimodal distribution for microscopic parameters of a cell (such as porosity, tortuosity, reaction kinetics, volumetric thermal conductivity, and volumetric heat capacity). The compounded effect of manufacturing variability, topological selection, cooling strategies, and cell balancing ages each cell in a battery differently. The study aims to clarify whether the challenge in extracting maximum information depends on the minimum number of sensors or models used for data extraction.

Automation↗
NASA NTRS1972

Lyman-alpha measurements of neutral hydrogen in the outer geocorona and in interplanetary space.

Results of hydrogen Lyman-alpha (1216 A) measurements made on a continuous basis by a two-channel photometer on Ogo 5 from March 1968 to June 1971. The highly elliptical orbit provided measurements of both the outer geocorona and of the 1216-A sky background emission, since geocoronal scattering is minimal at the apogee distance of 150,000 km. Selected data (through 1970) are presented, as well as an interpretation of the three principal discoveries to date - namely, (1) a pronounced antisolar enhancement of the geocoronal scattering beyond 70,000 km, which is regarded as evidence for a hydrogen 'geotail' produced by solar Lyman-alpha radiation pressure; (2) a clear correlation of periodic variations in the sky background emission with solar activity associated with solar rotation; and (3) an annual variation of the 1216-A sky background emission, caused by the earth's orbital motion within the cavity created by the solar wind in the nearby interstellar hydrogen.

Thomas, G. E.↗
NASA NTRS1992

Investigation of microgravity effects on solidification phenomena of selected materials

A Get Away Special (GAS) experiment payload to investigate microgravity effects on solidification phenomena of selected experimental samples has been designed for flight. It is intended that the first flight of the assembly will (1) study the p-n junction characteristics for advancing semiconductor device applications, (2) study the effects of gravity-driven convection on the growth of HgCd crystals, (3) compare the textures of the sample which crystallizes in microgravity with those found in chondrite meteorites, and (4) modify glass optical characteristics through divalent oxygen exchange. The space flight experiment consists of many small furnaces. While the experiment payload is in the low gravity environment of orbital flight, the payload controller will sequentially activate the furnaces to heat samples to their melt state and then allow cooling to resolidification in a controlled fashion. The materials processed in the microgravity environment of space will be compared to the same materials processed on earth in a one-gravity environment. This paper discusses the design of all subassemblies (furnance, electronics, and power systems) in the experiment. A complete description of the experimental materials is also presented.

Maag, Carl R.↗
NASA NTRS1985

Electroencephalogram (EEG) and Magnetoencephalogram (MEG) as Tools for Evaluation of Cognitive Function

We have developed computerized analysis and display techniques to help identify the origins of visually evoked scalped potentials (VESP). The potentials are recorded simultaneously from many electrodes (usually 40 to 48) spaced over the region of the scalp where appreciable evoked potentials are found in response to particular stimulus. Contour mapping algorithms are then used to display the time behavior of equipotential surfaces on the scalp during the VESP. We then use an optimization technique to select the parameters of arrays of current dipole sources within the model until the model equipotential field distribution closely fits the measured data. Computer graphics are then used to display, as a movie, the actual and model scalp potential fields and the parameters of the dipole generators within the model head during the course of VESP activity. We have devised reaction time tests that involve potentially separable stages of cognitive processing and utilize stimuli that produce measurable cognition-related features in the late component of the evoked potential. We have used these techniques to determine the loci in the brain where known cognition-related features in the evoked potential are generated and we have explored the extent to which each of these features can be related to the reaction time tasks. We have also examined the temporal-spatial aspects of their cerebral involvement. Our current work is planned to characterize the age-related changes in the processes performed by such sources. We also use a neuromagnetometer to measure the evoked magnetic fields in similar circumstances; we will discuss the relative merits of the two methodologies.

Fender, Derek H.↗
NASA NTRS2007

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-loop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of"pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL) using the FRL's 6-DOF gantry system, called the Dynamic Overhead Target System (DOTS). The target vehicle for "docking" in the laboratory was a mockup that was representative of the proposed CEV docking system, with added retroreflectors for the AVGS. The multi-sensor test configuration used 35 open-loop test trajectories covering three major objectives: (1) sensor characterization trajectories designed to test a wide range of performance parameters; (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multi-sensor series of trajectories.

Brewster, L.↗
NASA NTRS2008

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Lab

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success ofthe Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-Ioop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of "pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL) using the FRL's 6-DOF gantry system, called the Dynamic Overhead Target System (DOTS). The target vehicle for "docking" in the laboratory was a mockup that was representative of the proposed CEV docking system, with added retroreflectors for the AVGS.' The multi-sensor test configuration used 35 open-loop test trajectories covering three major objectives: (l) sensor characterization trajectories designed to test a wide range of performance parameters; (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multisensor series oftrajectories

Brewster, Linda L.↗
NASA NTRS2008

Stereo and Solar Cycle 24

The twin STEREO spacecrafi, launched in October 2006, are in heliocentric orbits near 4 AU with one spacecraft (Ahead) leading Earth in its orbit around the Sun and the other (Behind) trailing Earth. As viewed from the Sun, the STEREO spacecraft are continually separating from one another at about 45 degrees per year with Earth biseding the angle. At present, th@spaser=raft are a bit more than 45 degrees apart, thus they are able to each 'vie@ ground the limb's of the Sun by about 23 degrees, corresponding to about 1.75 days of solar rotation. Both spameraft contain an identical set of instruments including an extreme ultraviolet imager, two white light coronagraphs, tws all-sky imagers, a wide selection of energetic particle detectors, a magnetometer and a radio burst tracker. A snapshot of the real time data is continually broadcast to NOW-managed ground stations and this small stream of data is immediately sent to the STEREO Science Center and converted into useful space weather data within 5 minutes of ground receipt. The resulting images, particle, magnetometer and radio astronomy plots are available at ~ ~ j ~ g ~ ~ ~ i t , : gAs~ timqe~ co~n~ting ue~s ijnto~ ~ ~ ~ ~ . ~ g ~ solar cycle 24, the separation angle becomes 90 degrees in early 2009 and 180 degrees in early 201 1 as the activity heads toward maximum. By the time of solar maximum, STEREO will provide for the first time a view of the entire Sun with the mronagraphs and e*reme ultraviolet instruments. This view wilt allow us to follow the evolution of active regions continuously and also detect new active regions long before they pose a space weather threat to Earth. The in situ instruments will be able to provide about 7 days advanced notice of co-rotating structures in the solar wind. During this same intewal near solar maximum, the wide-angle imagers on STEREB will both be ;able to view EarlCP-dirsted CMEs in their plane-oPsky. When combined with Eat-lhorbiting assets available at that time, it seems solar cycle 24 will mark a great increase in our ability to understand and predict space weather.

Kaise,r Michael L.↗
NASA NTRS2020

Extravehicular Activity (EVA) Office Exploration EVA System Technical Standards

The purpose of this Extravehicular Activity (EVA) Office specification is to define the types of Programmatic-level standards to be used for design, manufacturing, testing, and quality control for the Exploration EVA (xEVA) System. The xEVA system includes both space suits and EVA hardware elements (e. EVA Tools, Airlock hardware, etc.). Many of the standards referenced in this document can be substituted for similar standards used in industry; this document provides the scope of which standards need to be considered. This document is the EVA-centric implementation of Chapter 3 of NPR 7120.10, Technical Standards for National Aeronautics and Space Administration (NASA) Programs and Projects: Select technical standards for use as program/project requirements. This also addresses the intent of Section 2.2.6 of NPR 8705.2, Human-Rating Requirements for Space Systems.

EVA↗
NASA NTRS2011

An Update on Experimental Climate Prediction and Analysis Products Being Developed at NASA's Global Modeling and Assimilation Office

The Global Modeling and Assimilation Office at NASA's Goddard Space Flight Center is developing a number of experimental prediction and analysis products suitable for research and applications. The prediction products include a large suite of subseasonal and seasonal hindcasts and forecasts (as a contribution to the US National MME), a suite of decadal (10-year) hindcasts (as a contribution to the IPCC decadal prediction project), and a series of large ensemble and high resolution simulations of selected extreme events, including the 2010 Russian and 2011 US heat waves. The analysis products include an experimental atlas of climate (in particular drought) and weather extremes. This talk will provide an update on those activities, and discuss recent efforts by WCRP to leverage off these and similar efforts at other institutions throughout the world to develop an experimental global drought early warning system.

Schubert, Siegfried↗
NASA NTRS2025

Countermeasures for Mitigation of Sensorimotor Decrements Following Head-Down Tilt Bed Rest

BACKGROUND Astronauts experience postflight disturbances in postural and locomotor control due to sensorimotor adaptations during spaceflight. These alterations may have adverse consequences if a rapid egress is required after landing. Although exercise is partially effective for mitigating cardiovascular and muscular deconditioning, additional countermeasures are needed to further preserve sensorimotor function. Proprioception training and electrical muscle stimulation (EMS) are two promising in-flight countermeasures. Since prolonged head down tilt bed rest (HDTBR) is a spaceflight analog for body unloading and causes postural and locomotor control decrements that parallel those observed after spaceflight, it can be used to facilitate the development of these countermeasures. METHODS This study will determine the effects of proprioception training and EMS on functional task performance and sensorimotor function following 60 days of 6° HDTBR. Subjects will be randomly assigned to one of four groups: 1) an EMS arm, 2) a proprioception training arm, 3) an exercise plus proprioceptive training arm, and 4) a control arm. The EMS countermeasure will include daily bilateral stimulation of selected bilateral lower extremity muscles (30 minutes per session). Proprioception training will be performed three days per week (25 minutes per session) consisting of body-loaded postural tasks in the horizontal position on an air bearing sled. Exercise training will mimic current protocols used on the International Space Station, but treadmill aerobic exercise will be replaced with additional cycling aerobic exercise. Primary outcome measures will include pre- and post- HDTBR functional tests that require high demand for dynamic control of postural stability. Secondary measures will be used to explore key physiological changes that underlie countermeasure benefits. All HDTBR and data collection activities will be completed by the German Aerospace Center (DLR) at the :envihab facility. Given the constrained samples size, a Bayesian modelling approach will be used to quantify the probability that there is an effect of a given magnitude. HARDWARE AND PROTOCOL DEVELOPMENT Final hardware modifications and protocol developments were completed in preparation for Campaign 1, which began in September 2024. These included shipment, setup, and operator training for the transportable gravity bed, horizontal squat device, foam obstacle course, EMS devices, leg dexterity system, foot sole skin sensitivity system, and Radiofrequency Echographic Multi Spectrometry (REMS) ultrasound device. In addition, specialized protocols were developed for data collection using DLR’s equipment, including muscle morphology magnetic resonance imaging (MRI), optical coherence tomography, venous blood flow MRI and ultrasound, muscle ultrasound and impedance, and skin blood flow ultrasound. We will present early data from the first campaign, which concluded in November, 2024. These will be compared with previous data from the recent 30-day HDTBR campaigns (Spaceflight associated neuro-ocular syndrome countermeasures (SANS-CM)) conducted at DLR. RELEVANCE The deliverable from this project will be proof-of-concept sensorimotor countermeasure designs for functional task performance with full assessment of efficacy in a spaceflight analog. If one or more countermeasures are effective, they will be translated for validation with the suite of operationally implemented in-flight countermeasures.

T R Macaulay↗
NASA NTRS1997

Land-use in Amazonia and the Cerrado of Brazil: State of Knowledge and GIS Database

We have assembled datasets to strengthen the LargeScale Biosphere Atmosphere Experiment in Amazonia (LBA). These datasets can now be accessed through the Woods Hole Research Center homepage (www.whrc.org), and will soon be linked to the Pre-LBA homepages of the Brazilian Space Research Institute's Center for Weather and Climate Prediction (Instituto de Pesquisas Espaciais, Centro de Previsao de Tempo e Estudos Climaticos, INPE/CPTEC) and through the Oak Ridge National Laboratory, Distributed Active Archive Center (ORNL/DMC). Some of the datasets that we are making available involved new field research and/or the digitization of data available in Brazilian government agencies. For example, during the grant period we conducted interviews at 1,100 sawmills across Amazonia to determine their production of sawn timber, and their harvest intensities. These data provide the basis for the first quantitative assessment of the area of forest affected each year by selective logging (Nepstad et al, submitted to Nature). We digitized the locations of all of the rural households in the State of Para that have been mapped by the Brazilian malaria combat agency (SUCAM). We also mapped and digitized areas of deforestation in the state of Tocantins, which is comprised largely of savanna (cerrado), an ecosystem that has been routinely excluded from deforestation mapping exercises.

Nepstad, Daniel C.↗
NASA NTRS2008

Intravenous Fluid Mixing in Normal Gravity, Partial Gravity, and Microgravity: Down-Selection of Mixing Methods

The missions envisioned under the Vision for Space Exploration will require development of new methods to handle crew medical care. Medications and intravenous (IV) fluids have been identified as one area needing development. Storing certain medications and solutions as powders or concentrates can both increase the shelf life and reduce the overall mass and volume of medical supplies. The powders or concentrates would then be mixed in an IV bag with Sterile Water for Injection produced in situ from the potable water supply. Fluid handling in microgravity is different than terrestrial settings, and requires special consideration in the design of equipment. This document describes the analyses and down-select activities used to identify the IV mixing method to be developed that is suitable for ISS and exploration missions. The chosen method is compatible with both normal gravity and microgravity, maintains sterility of the solution, and has low mass and power requirements. The method will undergo further development, including reduced gravity aircraft experiments and computations, in order to fully develop the mixing method and associated operational parameters.

Niederhaus, Charles E.↗
NASA NTRS2017

Astromaterials Curation Online Resources for Principal Investigators

The Astromaterials Acquisition and Curation office at NASA Johnson Space Center curates all of NASA's extraterrestrial samples, the most extensive set of astromaterials samples available to the research community worldwide. The office allocates ~1500 individual samples to researchers and students each year and has served the planetary research community for 45+ years. The Astromaterials Curation office provides access to its sample data repository and digital resources to support the research needs of sample investigators and to aid in the selection and request of samples for scientific study. These resources can be found on the Astromaterials Acquisition and Curation website at https://curator.jsc.nasa.gov. To better serve our users, we have engaged in several activities to enhance the data available for astromaterials samples, to improve the accessibility and performance of the website, and to address user feedback. We havealso put plans in place for continuing improvements to our existing data products.

Todd, Nancy S.↗
NASA NTRS2024

Exploring Earth's Interface with Space: The Scientific Case for a Satellite Mission to the Lower Thermosphere-Ionosphere Transition Region

The ESA-NASA Lower Thermosphere-Ionosphere Science (ENLoTIS) Working Group was formed in May 2022 to cooperatively explore future lower thermosphere-ionosphere (LTI) satellite mission concepts, targeting very low altitudes (100-200 km) with in situ sampling of relevant geophysical parameters associated with the neutral atmosphere, the ionosphere’s plasma, electromagnetic fields, and energetic particles, which, together with modeling, would enable significant advancements in the understanding of neutral-ion interactions and other related science and space weather topics in this critical region of Geospace. The LTI region has been identified as one of considerable interest to both NASA and ESA. Most recently, the Daedalus mission study was carried out under the remit of ESA’s Earth Observation Programmes (EOP) Directorate competitive Earth Explorer 10 pre-feasibility (Phase 0) activities. Furthermore, many NASA studies have also focused on the LTI region, including both directed missions with dipping spacecraft, such as the initial TIMED dual-satellites and the GEC constellation, as well as numerous highly-rated Explorer proposals targeting the LTI. Although the Daedalus mission was not selected, the ESA Advisory Committee on Earth Observation (ACEO) ranked it highly on scientific grounds and encouraged further study activities to mature the concept, exploring potential international collaboration. Subsequent bilateral discussions with NASA’s Science Mission Directorate (SMD) noted that such a concept was in alignment with the 2020 SMD science plan – Science 2020-2024: A Vision for Scientific Excellence – along with other complimentary activities within the NASA Heliophysics Division. Building on NASA’s and ESA’s long history of very successful collaborations, this mutual interest in LTI science led to the establishment of a new inter-agency and cross-discipline science connection, linking the ESA EOP Climate Action, Sustainability and Science Department and the NASA Heliophysics Division. Initial exploratory discussions led to the formation of the ENLoTIS Working Group, which was directed to explore the science case behind a potential joint LTI mission. Members of the ENLoTIS Working Group are listed below, consisting of 7 scientists from ESA Member and Cooperating States and 7 scientists from the United States. The working group held 3 “in person” meetings over the course of 18 months, interspersed with regular virtual meetings on a more frequent basis. This report constitutes their chief findings and recommendations.

thermosphere↗
NASA NTRS1980

Evaluation of KU-band SPA and EA-1 software, task no. 2

The software for selected space shuttle components are examined for potential problem areas and possible suboptimal coding techniques. Errors discovered in the procedure termination routine are discussed. The technique used to store status flags is found not to be as efficient as possible, from both the standpoints of memory usage and processing time. Self-test routines are examined with the intent of providing a more detailed description of multiplexer/demultiplexer and display and control outputs. An example of a reconfiguration is presented with a block diagram to indicate the critical paths. A cross-reference table of status flags is given to aid in tracing the functional activity of software modules.

Dobbs, J.↗
NASA NTRS1990

Space Transportation Engine Program (STEP), phase B

The Space Transportation Engine Program (STEP) Phase 2 effort includes preliminary design and activities plan preparation that will allow smooth and time transition into a Prototype Phase and then into Phases 3, 4, and 5. A Concurrent Engineering approach using Total Quality Management (TQM) techniques, is being applied to define an oxygen-hydrogen engine. The baseline from Phase 1/1' studies was used as a point of departure for trade studies and analyses. Existing STME system models are being enhanced as more detailed module/component characteristics are determined. Preliminary designs for the open expander, closed expander, and gas generator cycles were prepared, and recommendations for cycle selection made at the Design Concept Review (DCR). As a result of July '90 DCR, and information subsequently supplied to the Technical Review Team, a gas generator cycle was selected. Results of the various Advanced Development Programs (ADP's) for the Advanced Launch Systems (ALS) were contributive to this effort. An active vehicle integration effort is supplying the NASA, Air Force, and vehicle contractors with engine parameters and data, and flowing down appropriate vehicle requirements. Engine design and analysis trade studies are being documented in a data base that was developed and is being used to organize information. To date, seventy four trade studies were input to the data base.

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