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At least 487 records · Page 27

NASA Astronauts on Soyuz: Experience and Lessons for the Future

The U. S., Russia, and, China have each addressed the question of human-rating spacecraft. NASA's operational experience with human-rating primarily resides with Mercury, Gemini, Apollo, Space Shuttle, and International Space Station. NASA s latest developmental experience includes Constellation, X38, X33, and the Orbital Space Plane. If domestic commercial crew vehicles are used to transport astronauts to and from space, Soyuz is another example of methods that could be used to human-rate a spacecraft and to work with commercial spacecraft providers. For Soyuz, NASA's normal assurance practices were adapted. Building on NASA's Soyuz experience, this report contends all past, present, and future vehicles rely on a range of methods and techniques for human-rating assurance, the components of which include: requirements, conceptual development, prototype evaluations, configuration management, formal development reviews (safety, design, operations), component/system ground-testing, integrated flight tests, independent assessments, and launch readiness reviews. When constraints (cost, schedule, international) limit the depth/breadth of one or more preferred assurance means, ways are found to bolster the remaining areas. This report provides information exemplifying the above safety assurance model for consideration with commercial or foreign-government-designed spacecraft. Topics addressed include: U.S./Soviet-Russian government/agency agreements and engineering/safety assessments performed with lessons learned in historic U.S./Russian joint space ventures

Source record↗

A unique facility for V/STOL aircraft hover testing

The paper discusses the Navy's XFV-12A tethered hover testing capabilities utilizing NASA's Impact Dynamic Research Facility (IDRF) at Langley. The facility allows for both static and dynamic tethered hover test operations to be undertaken with safety. The installation which consists of the 'Z' system (tether), restraint system, static tiedowns and the control room and console, is presented in detail. Among the capabilities demonstrated were the ability to recover the aircraft anytime during a test, to rapidly and safely define control limits, and to provide a realistic environment for pilot training and proficiency in VTOL flight.

Culpepper, R. G.↗

X-29A aircraft structural loads flight testing

The X-29A research and technology demonstrator aircraft has completed a highly successful multiphase flight test program. The primary research objective was to safely explore, evaluate, and validate a number of aerodynamic, structural, and flight control technologies, all highly integrated into the vehicle design. Most of these advanced technologies, particularly the forward-swept-wing platform, had a major impact on the structural design. Throughout the flight test program, structural loads clearance was an ongoing activity to provide a safe maneuvering envelope sufficient to accomplish the research objectives. An overview is presented of the technologies, flight test approach, key results, and lessons learned from the structural flight loads perspective. The overall design methodology was considered validated, but a number of structural load characteristics were either not adequately predicted or totally unanticipated prior to flight test. While conventional flight testing techniques were adequate to insure flight safety, advanced analysis tools played a key role in understanding some of the structural load characteristics, and in maximizing flight test productivity.

Sims, Robert↗

An Overview of an Experimental Demonstration Aerotow Program

An overview of an experimental demonstration of aerotowing a delta-wing airplane with low-aspect ratio and relatively high wing loading is presented. Aerotowing of future space launch configurations is a new concept, and the objective of the work described herein is to demonstrate the aerotow operation using an airplane configuration similar to conceptual space launch vehicles. Background information on the use of aerotow for a space launch vehicle is presented, and the aerotow system used in this demonstration is described. The ground tests, analytical studies, and flight planning used to predict system behavior and to enhance flight safety are detailed. The instrumentation suite and flight test maneuvers flown are discussed, preliminary performance is assessed, and flight test results are compared with the preflight predictions.

Murray, James E.↗

A Variable Stability Test Vehicle for ITS Applications

A variable stability test bed is under development for the National Highway Traffic Safety Administration (NHTSA). The Variable Dynamic Testbed Vehicle (VDTV) is being designed for research and testing of advanced collision warning and avoidance technologies being developed by industry and most likely being made available to consumers in the near future.

technologies↗

Full-Scaled Advanced Systems Testbed: Ensuring Success of Adaptive Control Research Through Project Lifecycle Risk Mitigation

The National Aeronautics and Space Administration's Dryden Flight Research Center completed flight testing of adaptive controls research on the Full-Scale Advance Systems Testbed (FAST) in January of 2011. The research addressed technical challenges involved with reducing risk in an increasingly complex and dynamic national airspace. Specific challenges lie with the development of validated, multidisciplinary, integrated aircraft control design tools and techniques to enable safe flight in the presence of adverse conditions such as structural damage, control surface failures, or aerodynamic upsets. The testbed is an F-18 aircraft serving as a full-scale vehicle to test and validate adaptive flight control research and lends a significant confidence to the development, maturation, and acceptance process of incorporating adaptive control laws into follow-on research and the operational environment. The experimental systems integrated into FAST were designed to allow for flexible yet safe flight test evaluation and validation of modern adaptive control technologies and revolve around two major hardware upgrades: the modification of Production Support Flight Control Computers (PSFCC) and integration of two, fourth-generation Airborne Research Test Systems (ARTS). Post-hardware integration verification and validation provided the foundation for safe flight test of Nonlinear Dynamic Inversion and Model Reference Aircraft Control adaptive control law experiments. To ensure success of flight in terms of cost, schedule, and test results, emphasis on risk management was incorporated into early stages of design and flight test planning and continued through the execution of each flight test mission. Specific consideration was made to incorporate safety features within the hardware and software to alleviate user demands as well as into test processes and training to reduce human factor impacts to safe and successful flight test. This paper describes the research configuration, experiment functionality, overall risk mitigation, flight test approach and results, and lessons learned of adaptive controls research of the Full-Scale Advanced Systems Testbed.

Pavlock, Kate M.↗

Aircraft fire safety research

During the past 15 years, very significant progress has been made toward enhancing aircraft fire safety in both normal and hostile (combat) operational environments. Most of the major aspects of the aircraft fire safety problem are touched upon here. The technology of aircraft fire protection, although not directly applicable in all cases to spacecraft fire scenarios, nevertheless does provide a solid foundation to build upon. This is particularly true of the extensive research and testing pertaining to aircraft interior fire safety and to onboard inert gas generation systems, both of which are still active areas of investigation.

Botteri, Benito P.↗

The Making of a Self-Neglect Severity Scale

Research in elder self-neglect has lagged behind that of other forms of mistreatment, despite the fact that self-neglect is the most common allegation reported to Adult Protective Service agencies throughout the US. The lack of a gold-standard to measure self-neglect has hampered efforts to study this phenomenon. Researchers designed the Self-neglect Severity Scale (SSS) based on interviews with Adult Protective Service workers and a national expert panel. The SSS is based on observation and interview and is administered in the home to include an environmental assessment. It was piloted, extensively field tested and then revised. The CREST SSS was developed using survey data and consultation with experts in the field. This instrument utilizes observer ratings, interview responses, and assesses subjects physical and environmental domains. It also assesses functional status as it relates to health and safety issues. After field and pilot testing the SSS was finalized and is currently undergoing reliability and validity testing. The CREST SSS was developed as a state scale to provide a common language for describing cases of self-neglect. It is the first self-neglect severity scale available to researchers. If found to be both reliable and valid it can be used in future intervention studies.

Smith, Scott M.↗

Structural Element Testing in Support of the Design of the NASA Composite Crew Module

In January 2007, the NASA Administrator and Associate Administrator for the Exploration Systems Mission Directorate chartered the NASA Engineering and Safety Center (NESC) to design, build, and test a full-scale Composite Crew Module (CCM). For the design and manufacturing of the CCM, the team adopted the building block approach where design and manufacturing risks were mitigated through manufacturing trials and structural testing at various levels of complexity. Following NASA's Structural Design Verification Requirements, a further objective was the verification of design analysis methods and the provision of design data for critical structural features. Test articles increasing in complexity from basic material characterization coupons through structural feature elements and large structural components, to full-scale structures were evaluated. This paper discusses only four elements tests three of which include joints and one that includes a tapering honeycomb core detail. For each test series included are specimen details, instrumentation, test results, a brief analysis description, test analysis correlation and conclusions.

Kellas, Sotiris↗

PE99155 Point-Of-Load Buck Regulator Total Ionizing Dose Test Report

Teledyne’s PE99155 point-of-load buck regulator was tested to evaluate an applicationspecific question about the start-up behavior of the device. This test determined if accumulated total ionizing dose (TID) affected any start-up voltage transient characteristics. Testing was based on pass/fail criterial for the magnitude of the output voltage to ensure the safety of downstream electronics. Two sets of radiation tests were performed. The first group of PE99155s used a high dose rate (HDR) irradiation to 25 krad(Si). A second group of PE99155s used high dose rate irradiation to 30 krad(Si).

TID↗

An Overview of the NASA Lift+Cruise eVTOL Crash Test

Introduction – NASA RVLT Project Impact Dynamics / Crash Safety Task - Task Objective: “To improve the crashworthiness and impact safety of Urban Air Mobility (UAM) vehicle and provide data to simplify the certification process. Efforts will include development of validated computational models of these vehicles, as well as other impacting bodies such as birds and drones. Efforts will also focus on developing and evaluating energy absorbing and crush properties of emerging and non-traditional composite materials and processes. Finally, occupant protection will be addressed using computational models and physical assets as it pertains to all rotorcraft environments.” - Problem Statement: “There currently is a lack of data for requirements regarding the crashworthy performance of UAM vehicles and impact loads generated by a bird strike. To address this technology gap, NASA will develop test guidelines, adopt modeling methodologies demonstrating capability for ‘certification by analysis’, acquire vehicle and occupant data on full-scale representative vehicles, and provide data/guidance to consensus standards organizations and the UAM community.” - 4 Main focus points - The investigation of occupant injury using physical and computational assets - The development of energy absorbing technology - The generation of data from sub- and full-scale crash test data - The execution of advanced finite element modelling techniques

evtol↗

Performance Testing of Yardney MCMB-LiNiCoAlO2 Lithium-ion Cells Possessing Electrolytes with Improved Safety Characteristics

Many future NASA missions aimed at exploring the Moon and Mars require high specific energy rechargeable batteries that possess enhanced safety characteristics. There is also a strong desire to develop Li-ion batteries with improved safety characteristics for terrestrial applications, most notably for HEV and PHEV automotive applications. In previous work focused upon evaluating various potential flame retardant additives1, triphenyl phosphate (TPP)2 was observed to have the most desirable attributes, including good life characteristics and resilience to high voltage operation. We have employed a number of approaches in the design of promising TPP-based electrolytes with improved safety, including: (a) varying the flame retardant additive (FRA) content (from 5 to 15%), (b) the use of fluorinated co-solvents, (c) the use of additives to improve compatibility, and (c) the use of ester co-solvents to decrease the viscosity and increase the conductivity. In recent work, we have demonstrated a number of these electrolyte formulations to be compatible with a number of chemistries, including: MCMB carbon-LiNi0.8Co0.2O2, graphite-LiNi0.8Co0.15Al0.05O2, Li-Li(Li0.17Ni 0.25 Mn 0.58 )O2, Li-LiNiCoMnO2 and graphite- LiNiCoMnO2.3,4 In the current study, we have demonstrated the performance of a number of TPP-containing electrolytes in 7 Ah prototype MCMB-LiNiCoO2 cells. We will describe the results of a number of performance tests, including: a) 100% DOD cycle life testing at various temperatures, b) discharge rate characterization as a function of temperature, c) charge rate characterization as a function of temperature, and d) impedance as a function of temperature. In addition to displaying good life characteristics, being comparable to baseline chemistries, a number of cells were observed to provide good performance over a wide temperature range.

Li-ion batteries↗

International Space Station (ISS) Plasma Contactor Unit (PCU) Utilization Plan Assessment Update

The International Space Station (ISS) vehicle undergoes spacecraft charging as it interacts with Earth's ionosphere and magnetic field. The interaction can result in a large potential difference developing between the ISS metal chassis and the local ionosphere plasma environment. If an astronaut conducting extravehicular activities (EVA) is exposed to the potential difference, then a possible electrical shock hazard arises. The control of this hazard was addressed by a number of documents within the ISS Program (ISSP) including Catastrophic Safety Hazard for Astronauts on EVA (ISS-EVA-312-4A_revE). The safety hazard identified the risk for an astronaut to experience an electrical shock in the event an arc was generated on an extravehicular mobility unit (EMU) surface. A catastrophic safety hazard, by the ISS requirements, necessitates mitigation by a two-fault tolerant system of hazard controls. Traditionally, the plasma contactor units (PCUs) on the ISS have been used to limit the charging and serve as a "ground strap" between the ISS structure and the surrounding ionospheric plasma. In 2009, a previous NASA Engineering and Safety Center (NESC) team evaluated the PCU utilization plan (NESC Request #07-054-E) with the objective to assess whether leaving PCUs off during non-EVA time periods presented risk to the ISS through assembly completion. For this study, in situ measurements of ISS charging, covering the installation of three of the four photovoltaic arrays, and laboratory testing results provided key data to underpin the assessment. The conclusion stated, "there appears to be no significant risk of damage to critical equipment nor excessive ISS thermal coating damage as a result of eliminating PCU operations during non- EVA times." In 2013, the ISSP was presented with recommendations from Boeing Space Environments for the "Conditional" Marginalization of Plasma Hazard. These recommendations include a plan that would keep the PCUs off during EVAs when the space environment forecast input to the ISS charging model indicates floating potentials (FP) within specified limits. These recommendations were based on the persistence of conditions in the space environment due to the current low solar cycle and belief in the accuracy and completeness of the ISS charging model. Subsequently, a Noncompliance Report (NCR), ISS-NCR-232G, Lack of Two-fault Tolerance to EVA Crew Shock in the Low Earth Orbit Plasma Environment, was signed in September 2013 specifying new guidelines for the use of shock hazard controls based on a forecast of the space environment from ISS plasma measurements taken prior to the EVA [ISS-EVA-312-AC, 2012]. This NESC assessment re-evaluates EVA charging hazards through a process that is based on over 14 years of ISS operations, charging measurements, laboratory tests, EMU studies and modifications, and safety reports. The assessment seeks an objective review of the plasma charging hazards associated with EVA operations to determine if any of the present hazard controls can safely change the PCU utilization plan to allow more flexibility in ISS operations during EVA preparation and execution.

Hernandez-Pellerano, Amri↗

Buffet test in the National Transonic Facility

A buffet test of a commercial transport model was accomplished in the National Transonic Facility at the NASA Langley Research Center. This aeroelastic test was unprecedented for this wind tunnel and posed a high risk for the facility. Presented here are the test results from a structural dynamics and aeroelastic response point of view. The activities required for the safety analysis and risk assessment are described. The test was conducted in the same manner as a flutter test and employed on-board dynamic instrumentation, real time dynamic data monitoring, and automatic and manual tunnel interlock systems for protecting the model.

Young, Clarence P., Jr.↗

Relative Navigation Light Detection and Ranging (LIDAR) Sensor Development Test Objective (DTO) Performance Verification

The NASA Engineering and Safety Center (NESC) received a request from the NASA Associate Administrator (AA) for Human Exploration and Operations Mission Directorate (HEOMD), to quantitatively evaluate the individual performance of three light detection and ranging (LIDAR) rendezvous sensors flown as orbiter's development test objective on Space Transportation System (STS)-127, STS-133, STS-134, and STS-135. This document contains the outcome of the NESC assessment.

Dennehy, Cornelius J.↗

Evaluating Material Flammability in Microgravity and Martian Gravity Compared to the NASA Standard Normal Gravity Test

Drop tower tests are conducted at Martian gravity to determine the flammability of three materials compared to previous tests in other normal gravity and reduced gravity environments. The comparison is made with consideration of a modified NASA standard test protocol. Material flammability limits in the different gravity and flow environments are tabulated to determine the factor of safety associated with normal gravity flammability screening. Previous testing at microgravity and Lunar gravity indicated that some materials burned to lower oxygen concentrations in low gravity than in normal gravity, although the low g extinction limit criteria are not the same as 1g due to time constraints in drop testing. Similarly, the data presented in this paper for Martian gravity suggest that there is a gravity level below Earth s at which materials burn more readily than on Earth. If proven for more materials, this may indicate the need to include a factor of safety on 1g flammability limits.

Oslon, Sandra. L.↗

Training and certification program of the operating staff for a 90-day test of a regenerative life support system

Prior to beginning a 90-day test of a regenerative life support system, a need was identified for a training and certification program to qualify an operating staff for conducting the test. The staff was responsible for operating and maintaining the test facility, monitoring and ensuring crew safety, and implementing procedures to ensure effective mission performance with good data collection and analysis. The training program was designed to ensure that each operating staff member was capable of performing his assigned function and was sufficiently cross-trained to serve at certain other positions on a contingency basis. Complicating the training program were budget and schedule limitations, and the high level of sophistication of test systems.

Source record↗

Launch Vehicle Sizing Benefits Utilizing Main Propulsion System Crossfeed and Project Status

To meet the goals for a next generation Reusable Launch Vehicle (RLV), a unique propulsion feed system concept was identified using crossfeed between the booster and orbiter stages that could reduce the Two-Stage-to-Orbit (TSTO) vehicle weight and Design, Development, Test and Evaluation (DDT&E) costs by approximately 25%, while increasing safety and reliability. The Main Propulsion System (MPS) crossfeed water demonstration test program addresses all activities required to reduce the risks for the MPS crossfeed system from a Technology Readiness Level (TRL) of 2 to 4 by the completion of testing and analysis by June 2003. During the initial period, that ended in March 2002, a subscale water flow test article was defined. Procurement of a subscale crossfeed check valve was initiated and the specifications for the various components were developed. The fluid transient and pressurization analytical models were developed separately and successfully integrated. The test matrix for the water flow test was developed to correlate the integrated model. A computational fluid dynamics (CFD) model of the crossfeed check valve was developed to assess flow disturbances and internal flow dynamics. Based on the results, the passive crossfeed system concept was very feasible and offered a safe system to be used in an RLV architecture. A water flow test article was designed to accommodate a wide range of flows simulating a number of different types of propellant systems. During the follow-on period, the crossfeed system model will be further refined, the test article will be completed, the water flow test will be performed, and finally the crossfeed system model will be correlated with the test data. This validated computer model will be used to predict the full-scale vehicle crossfeed system performance.

Chandler, Frank↗