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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

NASA's International Lunar Network Anchor Nodes and Robotic Lunar Lander Project Update

NASA Marshall Space Flight Center and The Johns Hopkins University Applied Physics Laboratory have been conducting mission studies and performing risk reduction activities for NASA's robotic lunar lander flight projects. Additional mission studies have been conducted to support other objectives of the lunar science and exploration community and extensive risk reduction design and testing has been performed to advance the design of the lander system and reduce development risk for flight projects.

Cohen, Barbara A.↗
NASA NTRS2007

Astronaut Risk Levels During Crew Module (CM) Land Landing

The NASA Engineering Safety Center (NESC) is investigating the merits of water and land landings for the crew exploration vehicle (CEV). The merits of these two options are being studied in terms of cost and risk to the astronauts, vehicle, support personnel, and general public. The objective of the present work is to determine the astronaut dynamic response index (DRI), which measures injury risks. Risks are determined for a range of vertical and horizontal landing velocities. A structural model of the crew module (CM) is developed and computational simulations are performed using a transient dynamic simulation analysis code (LS-DYNA) to determine acceleration profiles. Landing acceleration profiles are input in a human factors model that determines astronaut risk levels. Details of the modeling approach, the resulting accelerations, and astronaut risk levels are provided.

Lawrence, Charles↗
NASA NTRS2022

Interim Measure Report Revision 0: Un-Numbered Operational Areas PRL 229

This report documents the Interim Measure (IM) completed at Un-Numbered Operational Areas (UNOA) potential release location (PRL) 229, at Kennedy Space Center (KSC), Florida. This document has been prepared for the National Aeronautics and Space Administration (NASA), in accordance with HydroGeoLogic, Inc.’s (HGL) Contract 80KSC019D0012, Task Order 80KSC019F0224. The purpose of this IM report is to document the field results of the 2022 IM conducted between December 13, 2021, and February 11, 2022, and to present the recommendations based on the IM findings. IM activities were completed at the UNOA PRL 229 to remove railroad ties and benzo(a)pyrene equivalent (BAPE)/total recoverable petroleum hydrocarbons (TRPH)-affected soil in accordance with the IM Work Plan (IMWP) (Jacobs/CORE, 2019a). The objectives of the IM were to mitigate human health risks by reducing site contaminants to the residential soil cleanup target level (SCTL) based on the 95 percent upper confidence limit on the mean. A second objective was to reduce low molecular weight and high molecular weight polynuclear aromatic hydrocarbon (PAH) concentrations below ecological screening values for terrestrial receptors. Prior to excavation operations, railroad ties from all areas were consolidated. In total, 50.67 tons of railroad ties were transported from the site to JED Landfill in St. Cloud, Florida. The cumulative excavation footprint spanned an area of 9,710 square ft. In total, 908.54 tons of soil was transported from the site to JED Landfill. To backfill the excavation area, 880 cubic yards of clean fill was trucked to the site from S&LMaterials, Inc. borrow pit in Christmas, Florida. Following completion of backfill, the site restoration activities included grading the disturbed areas to match the existing elevations and vegetation planting by the site restoration subcontractor. The IM implementation activities were presented to the KSC Remediation Team during its meeting on May 3, 2022. The Remediation Team reached consensus on the completion of the IM reducing the area affected by BAPE/TRPH above the State of Florida residential soil cleanup target levels.

PAHs↗
NASA NTRS2013

Jettison Engineering Trajectory Tool

The Jettison Engineering Trajectory Tool (JETT) performs the jettison analysis function for any orbiting asset. It provides a method to compute the relative trajectories between an orbiting asset and any jettisoned item (intentional or unintentional) or sublimating particles generated by fluid dumps to assess whether an object is safe to jettison, or if there is a risk with an item that was inadvertently lost overboard. The main concern is the interaction and possible recontact of the jettisoned object with an asset. This supports the analysis that jettisoned items will safely clear the vehicle, ensuring no collisions. The software will reduce the jettison analysis task from one that could take days to complete to one that can be completed in hours, with an analysis that is more comprehensive than the previous method. It provides the ability to define the jettison operation relative to International Space Station (ISS) structure, and provides 2D and 3D plotting capability to allow an analyst to perform a subjective clearance assessment with ISS structures. The developers followed the SMP to create the code and all supporting documentation. The code makes extensive use of the object-oriented format of Java and, in addition, the Model-View-Controller architecture was used in the organization of the code, allowing each piece to be independent of updates to the other pieces. The model category is for maintaining data entered by the user and generated by the analysis. The view category provides capabilities for data entry and displaying all or a portion of the analysis data in tabular, 2D, and 3D representation. The controller category allows for handling events that affect the model or view(s). The JETT utilizes orbital mechanics with complex algorithms. Since JETT is written in JAVA, it is essentially platform-independent.

Zaczek, Mariusz↗
NASA NTRS1979

Risk methodology overview

Some considerations of risk estimation, how risk is measured, and how risk analysis decisions are made are discussed. Specific problems of carbon fiber release are discussed by reviewing the objective, describing the main elements, and giving an example of the risk logic and outputs.

Credeur, K. R.↗
NASA NTRS2019

Development and Analysis of the Automated Object Reentry Survival Analysis Tool Parametric Study Wrapper

The NASA Orbital Debris Program Office (ODPO) studies all aspects of spacecraft end-of-life and orbital debris measurement, modeling, and mitigation. The reentry safety group within the ODPO uses the Object Reentry Survival Analysis Tool (ORSAT) to calculate the casualty risk due to reentry of spacecraft and other types of orbital debris. ORSAT models spacecraft as a collection of fragments that break apart from the parent object at a pre-defined “breakup altitude.” It then calculates the trajectory and aero-heating of these fragments to determine which fragments are completely destroyed and which survive to the ground and pose a risk to human population. Because of the historically high computational cost of these calculations, many simplifying assumptions have been made in the traditional calculation and analysis process used by the ODPO, some of which have been shown by recent research by the ODPO and others to be incorrect. Improvements to the ORSAT code and advancements in computer technology have vastly decreased the program’s processing time, and have allowed the ODPO to develop a capability for large-scale parametric studies and Monte Carlo reentry simulations that can aid in both the initial spacecraft design and provide more detailed and accurate risk analysis to spacecraft operators.

Smith, Andrew N.↗
NASA NTRS2003

Risk-based analysis and decision making in multi-disciplinary environments

A risk-based decision-making process conceived of and developed at JPL and NASA, has been used to help plan and guide novel technology applications for use on spacecraft. These applications exemplify key challenges inherent in multi-disciplinary design of novel technologies deployed in mission-critical settings. 1) Cross-disciplinary concerns are numerous (e.g., spacecraft involve navigation, propulsion, telecommunications). These concems are cross-coupled and interact in multiple ways (e.g., electromagnetic interference, heat transfer). 2) Time and budget pressures constrain development, operational resources constrain the resulting system (e.g., mass, volume, power). 3) Spacecraft are critical systems that must operate correctly the first time in only partially understood environments, with no chance for repair. 4) Past experience provides only a partial guide: New mission concepts are enhanced and enabled by new technologies, for which past experience is lacking. The decision-making process rests on quantitative assessments of the relationships between three classes of information - objectives (the things the system is to accomplish and constraints on its operation and development), risks (whose occurrence detracts from objectives), and mitigations (options for reducing the likelihood and or severity of risks). The process successfully guides experts to pool their knowledge, using custom-built software to support information gathering and decision-making.

technology↗
NASA NTRS1992

Pre-flight risk assessment in Emergency Medical Service (EMS) helicopters

The Emergency Medical Service (EMS) industry has been the subject of several television and newspaper articles (Harvey and Jensen, 1987) which emphasized the negative aspects, (e.g., fatalities and high accident rates), rather than the life saving services performed. Until recently, the accident rate of the EMS industry has been five times as high as that of other civil helicopters. This high accident rate has been coupled with the dramatic rise in the number of programs. The industry has built from a single service at its inception in 1972, to over 180 in 1987 (Spray, 1987), to the point that 93 percent of the contiguous U.S. is now covered by some type of EMS service. These factors prompted the National Transportation Safety Board (NTSB) to study the accidents that occurred between May 11, 1978 and December 3, 1986 (NTSB, 1988). The NTSB report concluded that 'Sound pilot judgment is central to safe flight operations.' They further stated that '... factors unique to EMS helicopter operations--such as the influence of the mission itself, program competition, and EMS program management perspectives--can drastically influence pilot judgment during the EMS mission.' One of the most difficult decisions that a pilot must make is whether to accept or decline a mission. A pre-flight risk assessment system (SAFE) was developed at NASA-Ames Research Center for civil EMS operations to aid pilots in making this decision objectively. The ability of the SAFE system to predict mission risk profiles was tested at an EMS facility. The results of this field study demonstrated that the usefulness of SAFE was highly dependent on the type of mission flown. SAFE is now being modified so that it can 'learn' with each mission flown. For example, after flying a mission to a particular site, an EMS pilot would input information about this mission into the system, such as new buildings, wires, or approach procedures. Then, the next time a pilot flew a similar mission or one to the same area, this additional information would be taken into account in computing a risk assessment.

Shively, R. J.↗
NASA NTRS1984

NASA's approach to the commercial use of space

NASA planning activities in the area of commercial development of space resources are reviewed. Examples of specific types of commercial space ventures are given, according to three different categories: new commercial high-technology ventures; new commercial application of existing space technology, and commercial ventures resulting from the transfer of existing space programs to the private sector. Basic objectives for reducing technical, financial and institutional risks for commercial space operations are considered. Attention is given to the cooperative working environment encouraged by Joint Endeavor Agreements (JEAs) and Technical Exchange Agreements (TEAs) between industrial organizations in the development of space systems. Benefits of the commercial development of space resources include the production of purer pharmaceuticals for the treatment of cancers, kidney diseases, and diabetes; and the development of ultra-pure semiconductor crystals for use in next generation electronic equipment.

Gillam, I. T., IV↗
NASA NTRS1988

An approach to the design of a simple, radiation hard, highly integrated and reliable, lightweight satellite bus

A spacecraft system concept has been developed which uses ion propulsion and a small, simple, lightweight design approach to carry out a focused lunar science mission. The design relies on existing technology to achieve high reliability and the possibility of a near-term launch. Key characteristics of the mission are highly focused objectives, low launch costs, minimization of development risks and design simplicity. The spacecraft for the lunar mission is described with particular emphasis on the design and reliability approaches used. The degree of adaptability of this basic class of spacecraft bus is discussed with particular emphasis on its application as a technology testbed vehicle. Several potential mission applications are reviewed.

Nock, K. T.↗
NASA NTRS1993

Planning: Management of predictability and uncertainty and keeping abreast of developments

The purpose of this study is to propose method to set up and control of a space mission plan such as that of the HERMES spaceplane. The interest of this subject, other than its complexity, is due to the need to manage imprecision and uncertainty during a mission, as well as changes in between missions. Under these conditions, the set up and control of a flight plan require certain special attention and this has led us to define a certain number of qualities: mastery of complexity in order to resolve conflicts between activities: configuration, resource and time management; consideration of various criteria such as risk minimization or the attainment of mission objectives; robustness and flexibility to allow for hazards and deviations from the norm during operation without having to draw up new plans; aptness for replanning by making changes to the plan without having to set up the whole plan again; and memorization and explanation facility in order to manage developments between missions.

Bastien-Thiry, Christophe↗
NASA NTRS1994

Modeling aerosol emissions from the combustion of composite materials

The use of advanced composite materials (ACM) in the B-2 bomber, composite armored vehicle, and F-22 advanced tactical fighter has rekindled interest concerning the health risk of burned or burning ACM. The objective of this work was to determine smoke production from burning ACM and its toxicity. A commercial version of the UPITT II combustion toxicity method developed at the University of Pittsburgh, and subsequently refined through a US Army-funded basic research project, was used to established controlled combustion conditions which were selected to evaluate real-world exposure scenarios. Production and yield of toxic species varied with the combustion conditions. Previous work with this method showed that the combustion conditions directly influenced the toxicity of the decomposition products from a variety of materials.

Roop, J. A.↗
NASA NTRS1999

[Component and System Level of the FASTRAC Engine]

The primary activities of Lee & Associates during the period 7/20/99 to 12/31/99 as specified in the referenced Purchase Order has been in direct support of the Advanced Space Technology Program OfFice's Core Propulsion Project. An independent review to assess the program readiness to conduct component and system level testing of the FASTRAC Engine and to proceed into Fabrication has been provided. This was accomplished through the identification of program weaknesses and potential failure areas and where applicable recommended solutions were suggested to the Program Office that would mitigate technical and program risk. The approach taken to satisfy the objectives has been for the contractor to provide a team of experts with relevant experience from past programs and a strong background of experience in the fields critical to the success of the program. The team participated in Test Planning, Test Readiness Reviews for system testing at Stennis Space Center, Anomaly Resolution Reviews, an Operations Audit, and data analysis. This approach worked well in satisfying the objectives and providing the Project Office with valuable information in real time and through monthly reports. During the month of December 1999 the primary effort involved the participation in anomaly resolution and the detailed review of the data from the final H3 and H4 test series performed on the FASTRAC engine in the b-2 Horizontal Test Facility at Stennis. The more significant findings and recommendations from this review are presented in this report.

Source record↗
NASA NTRS2002

Rocket Propellants Engine Design/Operations/Validation

Lockheed Martin Astronautics Operations (LMA) was competitively awarded a contract May 21, 2001 for next generation launch system architecture definition and technology maturation. The Second Generation Launch Vehicle Program objectives include reducing the technical and programmatic risk of proceeding to full scale development of the system by establishing requirements for the next generation launch system and maturing critical technologies needed by the system. LMA will conduct analyses and trades to optimize the architecture ETO elements including configuration, conceptual designs, and preliminary operations definition. To fully understand the engine and propellant trades were conducted by LMA to yield the optimized architecture system from the operability, reliability, safety, and cost perspectives. A government/industry team addressed the required trade studies, the parameters and weighting factors, and the most critical trades were addressed. This report summarizes the participation of JCM Consulting, Inc. in the propellant trade study.

Monk, Jan C.↗
NASA NTRS2003

Achieving Space Shuttle Abort-to-Orbit Using the Five-Segment Booster

The Five-Segment Booster design concept was evaluated by a team that determined the concept to be feasible and capable of achieving the desired abort-to-orbit capability when used in conjunction with increased Space Shuttle main engine throttle capability. The team (NASA Johnson Space Center, NASA Marshall Space Flight Center, ATK Thiokol Propulsion, United Space Alliance, Lockheed-Martin Space Systems, and Boeing) selected the concept that provided abort-to-orbit capability while: 1) minimizing Shuttle system impacts by maintaining the current interface requirements with the orbiter, external tank, and ground operation systems; 2) minimizing changes to the flight-proven design, materials, and processes of the current four-segment Shuttle booster; 3) maximizing use of existing booster hardware; and 4) taking advantage of demonstrated Shuttle main engine throttle capability. The added capability can also provide Shuttle mission planning flexibility. Additional performance could be used to: enable implementation of more desirable Shuttle safety improvements like crew escape, while maintaining current payload capability; compensate for off nominal performance in no-fail missions; and support missions to high altitudes and inclinations. This concept is a low-cost, low-risk approach to meeting Shuttle safety upgrade objectives. The Five-Segment Booster also has the potential to support future heavy-lift missions.

Craft, Joe↗
NASA NTRS2007

Screening of Potential Landing Gear Noise Control Devices at Virginia Tech For QTD II Flight Test

In support of the QTD II (Quiet Technology Demonstrator) program, aeroacoustic measurements of a 26%-scale, Boeing 777 main landing gear model were conducted in the Virginia Tech Stability Tunnel. The objective of these measurements was to perform risk mitigation studies on noise control devices for a flight test performed at Glasgow, Montana in 2005. The noise control devices were designed to target the primary main gear noise sources as observed in several previous tests. To accomplish this task, devices to reduce noise were built using stereo lithography for landing gear components such as the brakes, the forward cable harness, the shock strut, the door/strut gap and the lower truck. The most promising device was down selected from test results. In subsequent stages, the initial design of the selected lower truck fairing was improved to account for all the implementation constraints encountered in the full-scale airplane. The redesigned truck fairing was then retested to assess the impact of the modifications on the noise reduction potential. From extensive acoustic measurements obtained using a 63-element microphone phased array, acoustic source maps and integrated spectra were generated in order to estimate the noise reduction achievable with each device.

Ravetta, Patricio A.↗
NASA NTRS2003

Adaptive Effects on Locomotion Performance Following Exposure to a Rotating Virtual Environment

During long-duration spaceflight, astronauts experience alterations in vestibular and somatosensory cues that result in adaptive disturbances in balance and coordination upon return to Earth. These changes can pose a risk to crew safety and to mission objectives if nominal or emergency vehicle egress is required immediately following long-duration spaceflight. At present, no operational countermeasure is available to mitigate the adaptive sensorimotor component underlying the locomotor disturbances that occur after spaceflight. Therefore, the goal of this study is to develop an inflight training regimen that facilitates recovery of locomotor function after long-duration spaceflight. The countermeasure we are proposing is based on the concept of adaptive generalization. During this type of training the subject gains experience producing the appropriate adaptive motor behavior under a variety of sensory conditions and response constraints. As a result of this training a subject learns to solve a class of motor problems, rather than a specific motor solution to one problem, i.e., the subject learns response generalizability or the ability to "learn to learn." under a variety of environmental constraints. We are developing an inflight countermeasure built around treadmill exercise activities. By manipulating the sensory conditions of exercise by varying visual flow patterns, body load and speed we will systematically and repeatedly promote adaptive change in locomotor behavior. It has been shown that variable practice training increases adaptability to novel visuo-motor situations. While walking over ground in a stereoscopic virtual environment that oscillated in roll, subjects have shown compensatory torso rotation in the direction of scene rotation that resulted in positional variation away from a desired linear path. Thus, postural sway and locomotor stability in 1-g can be modulated by visual flow patterns and used during inflight treadmill training to promote adaptive generalization. The purpose of this study was to determine if adaptive modification in locomotor performance could be achieved by viewing simulated self-motion in a passive-immersive virtual ' environment over a prolonged period during treadmill locomotion.

Mulavara, A. P.↗
NASA NTRS2011

Engineering and Technology Challenges for Active Debris Removal

After more than fifty years of space activities, the near-Earth environment is polluted with man-made orbital debris. The collision between Cosmos 2251 and the operational Iridium 33 in 2009 signaled a potential collision cascade effect, also known as the "Kessler Syndrome", in the environment. Various modelling studies have suggested that the commonly-adopted mitigation measures will not be sufficient to stabilize the future debris population. Active debris removal must be considered to remediate the environment. This paper summarizes the key issues associated with debris removal and describes the technology and engineering challenges to move forward. Fifty-four years after the launch of Sputnik 1, satellites have become an integral part of human society. Unfortunately, the ongoing space activities have left behind an undesirable byproduct orbital debris. This environment problem is threatening the current and future space activities. On average, two Shuttle window panels are replaced after every mission due to damage by micrometeoroid or orbital debris impacts. More than 100 collision avoidance maneuvers were conducted by satellite operators in 2010 to reduce the impact risks of their satellites with respect to objects in the U.S. Space Surveillance Network (SSN) catalog. Of the four known accident collisions between objects in the SSN catalog, the last one, collision between Cosmos 2251 and the operational Iridium 33 in 2009, was the most significant. It was the first ever accidental catastrophic destruction of an operational satellite by another satellite. It also signaled the potential collision cascade effect in the environment, commonly known as the "Kessler Syndrome," predicted by Kessler and Cour-Palais in 1978 [1]. Figure 1 shows the historical increase of objects in the SSN catalog. The majority of the catalog objects are 10 cm and larger. As of April 2011, the total objects tracked by the SSN sensors were more than 22,000. However, approximately 6000 of them had yet to be fully processed and entered into the catalog. This population had been dominated by fragmentation debris throughout history. Before the anti-satellite test (ASAT) conducted by China in 2007, the fragmentation debris were almost all explosion fragments. After the ASAT test and the collision between Iridium 33 and Cosmos 2251, the ratio of collision fragments to explosion fragments was about one-to-one. It is expected that accidental collision fragments will further dominate the environment in the future.

Liou, Jer-Chyi↗