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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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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Locomotor Dysfunction after Spaceflight: Characterization and Countermeasure Development

Astronauts returning from space flight show disturbances in locomotor control manifested by changes in various sub-systems including head-trunk coordination, dynamic visual acuity, lower limb muscle activation patterning and kinematics (Glasauer, et al., 1995; Bloomberg, et al., 1997; McDonald, et al., 1996; 1997; Layne, et al., 1997; 1998, 2001, 2004; Newman, et al., 1997; Bloomberg and Mulavara, 2003). These post flight changes in locomotor performance, due to neural adaptation to the microgravity conditions of space flight, affect the ability of crewmembers especially after a long duration mission to egress their vehicle and perform extravehicular activities soon after landing on Earth or following a landing on the surface of the Moon or Mars. At present, no operational training intervention is available pre- or in- flight to mitigate post flight locomotor disturbances. Our laboratory is currently developing a gait adaptability training program that is designed to facilitate recovery of locomotor function following a return to a gravitational environment. The training program exploits the ability of the sensorimotor system to generalize from exposure to multiple adaptive challenges during training so that the gait control system essentially "learns to learn" and therefore can reorganize more rapidly when faced with a novel adaptive challenge. Ultimately, the functional goal of an adaptive generalization countermeasure is not necessarily to immediately return movement patterns back to "normal". Rather the training regimen should facilitate the reorganization of available sensorimotor sub-systems to achieve safe and effective locomotion as soon as possible after space flight. We have previously confirmed that subjects participating in adaptive generalization training programs, using a variety of visuomotor distortions and different motor tasks from throwing to negotiating an obstacle course as the dependent measure, can learn to enhance their ability to adapt to a novel sensorimotor environment (Roller et al., 2001; Cohen et al. 2005). Importantly, this increased adaptability is retained even one month after completion of the training period. Our laboratory is currently developing adaptive generalization training procedures and the associated flight hardware to implement such a training program, using variations of visual flow, subject loading, and treadmill speed; during regular in-flight treadmill operations.

Mulavara, A. P.↗
NASA NTRS2013

The GLAS Science Algorithm Software (GSAS) User's Guide Version 7

The Geoscience Laser Altimeter System (GLAS) is the primary instrument for the ICESat (Ice, Cloud and Land Elevation Satellite) laser altimetry mission. ICESat was the benchmark Earth Observing System (EOS) mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. From 2003 to 2009, the ICESat mission provided multi-year elevation data needed to determine ice sheet mass balance as well as cloud property information, especially for stratospheric clouds common over polar areas. It also provided topography and vegetation data around the globe, in addition to the polar-specific coverage over the Greenland and Antarctic ice sheets.This document is the final version of the GLAS Science Algorithm Software Users Guide document. It contains the instructions to install the GLAS Science Algorithm Software (GSAS) in the production environment that was used to create the standard data products. It also describes the usage of each GSAS program in that environment with their required inputs and outputs. Included are a number of utility programs that are used to create ancillary data files that are used in the processing but generally are not distributed to the public as data products. Of importance is the values for the large number of constants used in the GSAS algorithm during processing are provided in an appendix.

Lee, Jeffrey E.↗
NASA NTRS2006

Development of a Countermeasure to Mitigate Postflight Locomotor Dysfunction

Astronauts returning from space flight experience locomotor dysfunction following their return to Earth. Our laboratory is currently developing a gait adaptability training program that is designed to facilitate recovery of locomotor function following a return to a gravitational environment. The training program exploits the ability of the sensorimotor system to generalize from exposure to multiple adaptive challenges during training so that the gait control system essentially learns to learn and therefore can reorganize more rapidly when faced with a novel adaptive challenge. Evidence for the potential efficacy of an adaptive generalization gait training program can be obtained from numerous studies in the motor learning literature which have demonstrated that systematically varying the conditions of training enhances the ability of the performer to learn and retain a novel motor task. These variable practice training approaches have been used in applied contexts to improve motor skills required in a number of different sports. The central nervous system (CNS) can produce voluntary movement in an almost infinite number of ways. For example, locomotion can be achieved with many different combinations of joint angles, muscle activation patterns and forces. The CNS can exploit these degrees of freedom to enhance motor response adaptability during periods of adaptive flux like that encountered during a change in gravitational environment. Ultimately, the functional goal of an adaptive generalization countermeasure is not necessarily to immediately return movement patterns back to normal. Rather the training regimen should facilitate the reorganization of available sensory and motor subsystems to achieve safe and effective locomotion as soon as possible after long duration space flight. Indeed, this approach has been proposed as a basic feature underlying effective neurological rehabilitation. We have previously confirmed that subjects participating in an adaptive generalization training program using a variety of visuomotor distortions and throwing as the dependent measure can learn to enhance their ability to adapt to a novel sensorimotor environment (Roller et al., 2001). Importantly, this increased adaptability was retained even one month after completion of the training period. Adaptive generalization has been observed in a variety of other tasks requiring sensorimotor transformations including manual control tasks and reaching (Bock et al., 2001, Seidler, 2003) and obstacle avoidance during walking (Lam and Dietz, 2004). Taken together, the evidence suggests that a training regimen exposing crewmembers to variation in locomotor conditions, with repeated transitions among states, may enhance their ability to learn how to reassemble appropriate locomotor patterns upon return from microgravity. We believe exposure to this type of training will extend crewmembers locomotor behavioral repertoires, facilitating the return of functional mobility after long duration space flight. In other words, our proposed training protocol will compel subjects to develop new behavioral solutions under varying sensorimotor demands. Over time subjects will learn to create appropriate locomotor solution more rapidly enabling acquisition of mobility sooner after long-duration space flight. A gait adaptability training program can be superimposed on nominal treadmill exercise activities thus ensuring that no additional crew time is required to perform this type of training regimen and that it can be implemented with current in-flight exercise systems available on the International Space Station.

Bloomberg, J. J.↗
NASA NTRS1975

Environmental crack-growth behavior of high strength pressure vessel alloys

Results of sustained-load environmental crack growth threshold tests performed on six spacecraft pressure vessel alloys are presented. The alloys were Inconel 718, 6Al-4V titanium, A-286 steel, AM-350 stainless steel, cryoformed AISI 301 stainless steel; and cryoformed AISI 304L steel. The test environments for the program were air, pressurized gases of hydrogen, oxygen, nitrogen, and carbon dioxide, and liquid environments of distilled water, sea water, nitrogen tetroxide, hydrazine, aerozine 50, monomethyl hydrazine, and hydrogen peroxide. Surface flaw type specimens were used with flaws located in both base metal and weld metal.

Forman, R. G.↗
NASA NTRS1993

Program Helps In Analysis Of Failures

Failure Environment Analysis Tool (FEAT) computer program developed to enable people to see and better understand effects of failures in system. User selects failures from either engineering schematic diagrams or digraph-model graphics, and effects or potential causes of failures highlighted in color on same schematic-diagram or digraph representation. Uses digraph models to answer two questions: What will happen to system if set of failure events occurs? and What are possible causes of set of selected failures? Helps design reviewers understand exactly what redundancies built into system and where there is need to protect weak parts of system or remove them by redesign. Program also useful in operations, where it helps identify causes of failure after they occur. FEAT reduces costs of evaluation of designs, training, and learning how failures propagate through system. Written using Macintosh Programmers Workshop C v3.1. Can be linked with CLIPS 5.0 (MSC-21927, available from COSMIC).

Stevenson, R. W.↗
NASA NTRS2008

Using Space Weather Variability in Evaluating the Environment Design Specifications for NASA'S Constellation Program

Spectral models of solar particle events and trapped radiation belts are necessary for the design requirements of total ionizing radiation dose, single event effects, and spacecraft charging. Space radiation and plasma environment specifications for hardware design are necessarily conservative to assure system robustness for a wide range of space environments.

Coffey, Victoria N.↗
NASA NTRS1991

SRB Environment Evaluation and Analysis. Volume 2: RSRB Joint Filling Test/Analysis Improvements

Following the Challenger accident a very comprehensive solid rocket booster (SRB) redesign program was initiated. One objective of the program was to develop expertise at NASA/MSFC in the techniques for analyzing the flow of hot gases in the SRB joints. Several test programs were undertaken to provide a data base of joint performance with manufactured defects in the joints to allow hot gases to fill the joints. This data base was used also to develop the analytical techniques. Some of the test programs were Joint Environment Simulator (JES), Nozzle Joint Environment Simulator (NJES), Transient Pressure Test Article (TPTA), and Seventy-Pound Charge (SPC). In 1988 the TPTA test hardware was moved from the Utah site to MSFC and several RSRM tests were scheduled, to be followed by tests for the ASRM program. REMTECH Inc. supported these activities with pretest estimates of the flow conditions in the test joints, and post-test analysis and evaluation of the measurements. During this support REMTECH identified deficiencies in the gas-measurement instrumentation that existed in the TPTA hardware, made recommendations for its replacement, and identified improvements to the analytical tools used in the test support. Only one test was completed under the TPTA RSRM test program, and those scheduled for the ASRM were rescheduled to a time after the expiration of this contract. The attention of this effort was directed toward improvements in the analytical techniques in preparation for when the ASRM program begins.

Knox, E. C.↗
NASA NTRS1974

Behavior of ceramics at 1200 C in a simulated gas turbine environment

This report summarizes programs at the NASA Lewis Research Center evaluating several classes of commercial ceramics, in a high gas velocity burner rig simulating a gas turbine engine environment. Testing of 23 ceramics in rod geometry identified SiC and Si3N4 as outstanding in resistance to oxidation and thermal stress and identified the failure modes of other ceramics. Further testing of a group of 15 types of SiC and Si3N4 in simulated vane shape geometry has identified a hot pressed SiC, a reaction sintered SiC, and hot pressed Si3N4 as the best of that group. SiC and Si3N4 test specimens were compared on the basis of weight change, dimensional reductions, metallography, fluorescent penetrant inspection, X-ray diffraction analyses, and failure mode.

Sanders, W. A.↗
NASA NTRS1980

Development of a computer program data base of a navigation aid environment for simulated IFR flight and landing studies

A general aviation single pilot instrument flight rule simulation capability was developed. Problems experienced by single pilots flying in IFR conditions were investigated. The simulation required a three dimensional spatial navaid environment of a flight navigational area. A computer simulation of all the navigational aids plus 12 selected airports located in the Washington/Norfolk area was developed. All programmed locations in the list were referenced to a Cartesian coordinate system with the origin located at a specified airport's reference point. All navigational aids with their associated frequencies, call letters, locations, and orientations plus runways and true headings are included in the data base. The simulation included a TV displayed out-the-window visual scene of country and suburban terrain and a scaled model runway complex. Any of the programmed runways, with all its associated navaids, can be referenced to a runway on the airport in this visual scene. This allows a simulation of a full mission scenario including breakout and landing.

Bergeron, H. P.↗
NASA NTRS2011

Amine Swingbed Payload Project Management

The International Space Station (ISS) has been designed as a laboratory for demonstrating technologies in a microgravity environment, benefitting exploration programs by reducing the overall risk of implementing such technologies in new spacecraft. At the beginning of fiscal year 2010, the ISS program manager requested that the amine-based, pressure-swing carbon dioxide and humidity absorption technology (designed by Hamilton Sundstrand, baselined for the ORION Multi-Purpose Crew Vehicle, and tested at the Johnson Space Center in relevant environments, including with humans, since 2005) be developed into a payload for ISS Utilization. In addition to evaluating the amine technology in a flight environment before the first launch of the ORION vehicle, the ISS program wanted to determine the capability of the amine technology to remove carbon dioxide from the ISS cabin environment at the metabolic rate of the full 6-person crew. Because the amine technology vents the absorbed carbon dioxide and water vapor to space vacuum (open loop), additional hardware needed to be developed to minimize the amount of air and water resources lost overboard. Additionally, the payload system would be launched on two separate Space Shuttle flights, with the heart of the payload the swingbed unit itself launching a full year before the remainder of the payload. This paper discusses the project management and challenges of developing the amine swingbed payload in order to accomplish the technology objectives of both the open-loop ORION application as well as the closed-loop ISS application.

Hayley, Elizabeth↗
NASA NTRS2013

Amine Swingbed Payload Project Management

The International Space Station (ISS) has been designed as a laboratory for demonstrating technologies in a microgravity environment, benefitting exploration programs by reducing the overall risk of implementing such technologies in new spacecraft. At the beginning of fiscal year 2010, the ISS program manager requested that the amine-based, pressure-swing carbon dioxide and humidity absorption technology (designed by Hamilton Sundstrand, baselined for the Orion Multi-Purpose Crew Vehicle, and tested at the Johnson Space Center in relevant environments, including with humans, since 2005) be developed into a payload for ISS Utilization. In addition to evaluating the amine technology in a flight environment before the first launch of the Orion vehicle, the ISS program wanted to determine the capability of the amine technology to remove carbon dioxide from the ISS cabin environment at the metabolic rate of the full 6 ]person crew. Because the amine technology vents the absorbed carbon dioxide and water vapor to space vacuum (open loop), additional hardware needed to be developed to minimize the amount of air and water resources lost overboard. Additionally, the payload system would be launched on two separate Space Shuttle flights, with the heart of the payload-the swingbed unit itself-launching a full year before the remainder of the payload. This paper discusses the project management and challenges of developing the amine swingbed payload in order to accomplish the technology objectives of both the open -loop Orion application as well as the closed-loop ISS application.

Walsch, Mary↗
NASA NTRS1994

Laser Light Scattering, from an Advanced Technology Development Program to Experiments in a Reduced Gravity Environment

Recent advancements in laser light scattering hardware are described. These include intelligent single card correlators; active quench/active reset avalanche photodiodes; laser diodes; and fiber optics which were used by or developed for a NASA advanced technology development program. A space shuttle experiment which will employ aspects of these hardware developments is previewed.

Meyer, William V.↗
NASA NTRS2026

Gateway Element and Payload Materials Outgassing Analyses: HALO, HERMES, and ERSA

Gateway was intended to be humanity’s first space station around the Moon, but its development has been paused as the National Aeronautics and Space Administration (NASA) shifts focus to achieving the United States’ National Space Policy goals. Instead of an orbiting lunar outpost, NASA will now pursue the development of a lunar surface base to support a sustained human presence on the Moon. Before the program’s pause, Gateway’s Induced Environments team worked to ensure payloads and elements (i.e., modules) complied with induced environment requirements. Methods developed and insights gained from this work will have applicability to NASA’s Moon Base and the potential repurposing of Gateway elements and payloads, as well as to induced environments modeling for future space stations. The Gateway program’s induced environment included molecular contamination, electric thruster plume sputter and redeposition, and lunar dust transfer from the Human Landing System (HLS). Primary sources of external molecular contamination included materials outgassing, chemical thruster plume contamination, and vacuum venting. The focus of this paper will be on element- and payload-level materials outgassing analyses performed for Gateway Configuration 1, extending the previously-developed framework for Gateway system-level external molecular contamination modeling. Gateway Configuration 1 consisted of the Power and Propulsion Element (PPE) and the Habitation and Logistics Outpost (HALO). It also included payloads like the European Radiation Sensor Array (ERSA) attached to PPE and the Heliophysics Environmental and Radiation Measurement Experiment Suite (HERMES) attached to HALO. The element- and payload-level analyses to be introduced in this paper for HALO, HERMES, and ERSA enabled high-fidelity descriptions of Gateway’s external molecular contamination environment. Approaches to geometric modeling, meshing, outgassing rate assignment, molecular transport modeling, and analysis methodology will be presented. Element and payload contaminant deposition onto sensitive Gateway receiver surfaces will be summarized and results compared to induced environment requirements. While these results incorporate refinements made over the course of the program, they were not intended to be final. Therefore, modeling assumptions and inputs, potential improvements, and lessons-learned will be documented to inform future work on Moon Base, repurposed elements and payloads, and other space stations.

Gateway↗
NASA NTRS2002

Modeling and control for closed environment plant production systems

A computer program was developed to study multiple crop production and control in controlled environment plant production systems. The program simulates crop growth and development under nominal and off-nominal environments. Time-series crop models for wheat (Triticum aestivum), soybean (Glycine max), and white potato (Solanum tuberosum) are integrated with a model-based predictive controller. The controller evaluates and compensates for effects of environmental disturbances on crop production scheduling. The crop models consist of a set of nonlinear polynomial equations, six for each crop, developed using multivariate polynomial regression (MPR). Simulated data from DSSAT crop models, previously modified for crop production in controlled environments with hydroponics under elevated atmospheric carbon dioxide concentration, were used for the MPR fitting. The model-based predictive controller adjusts light intensity, air temperature, and carbon dioxide concentration set points in response to environmental perturbations. Control signals are determined from minimization of a cost function, which is based on the weighted control effort and squared-error between the system response and desired reference signal.

NASA Discipline Life Support Systems↗
NASA NTRS1977

Space industrialization studies - An overview

An overview of NASA's current planning for a space industrialization program is described as an introduction to the papers on Space Industrialization being presented by Rockwell International Corporation and Science Applications Incorporated. Background information is presented that outlines the integrated planning process which resulted in specific long range goals and objectives being formulated for NASA programs in technology, environment, resources, earth science, communications, space exploration, aeronautics, and an expanded application of space called space industrialization. Program objectives for NASA's Industrialization of Space and studies on potential near term supporting elements (Space Platform, Large Space Structures, Orbital Operations Capabilities Development, Space Manufacturing Module) are discussed.

Priest, C.↗
NASA NTRS1971

A computerized program for statistical treatment of biological data

Biologists frequently conduct experiments which measure the patterns of inactivation of bacterial populations after exposure to a lethal environment. A computer program is discussed which calculates many of the quantities that have proven to be useful in the analysis of such experimental data.

Roark, A. L.↗