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At least 865 records · Page 48

Structural assembly demonstration experiment

The experiment is of an operational variety, designed to assess crew capability in Large Space System (LSS) assembly. The six Structural Assembly Demonstration Experiment objectives include: (1) the establishment of a quantitative correlation between LSS neutral buoyancy simulation and on-orbit assembly operations in order to enhance the validity of those assembly simulations; (2) the quantitative study of the capabilities and mechanics of human assembly in an Extravehicular Activity environment; (3) the further corroboration of the LSS Assembly Analysis cost algorithm through the obtainment of hard data base information; (4) the verification of LSS assembly techniques and timeless, as well as the identification of crew imposed loads and assembly aid requirements and concepts; (5) verification of a Launch/Assembly Platform structure concept for other LSS missions; and (6) lastly, to advance thermal control concepts through a flexible heat pipe.

Stokes, J. W.↗

The Deep Space Network information system in the year 2000

The Deep Space Network (DSN), the largest, most sensitive scientific communications and radio navigation network in the world, is considered. Focus is made on the telemetry processing, monitor and control, and ground data transport architectures of the DSN ground information system envisioned for the year 2000. The telemetry architecture will be unified from the front-end area to the end user. It will provide highly automated monitor and control of the DSN, automated configuration of support activities, and a vastly improved human interface. Automated decision support systems will be in place for DSN resource management, performance analysis, fault diagnosis, and contingency management.

Markley, R. W.↗

Production Of Human Antibodies

Process for making human monoclonal antibodies based on combination of techniques. Antibodies made active against specific antigen. Process involves in vivo immunization of human B lymphocyte cells in mice. B cells of interest enriched in vitro before fusion. Method potentially applicable to any antigen. Does not rely on use of Epstein-Barr virus at any step. Human lymphocytes taken from any source.

Sammons, David W.↗

Multiagent Modeling and Simulation in Human-Robot Mission Operations Work System Design

This paper describes a collaborative multiagent modeling and simulation approach for designing work systems. The Brahms environment is used to model mission operations for a semi-autonomous robot mission to the Moon at the work practice level. It shows the impact of human-decision making on the activities and energy consumption of a robot. A collaborative work systems design methodology is described that allows informal models, created with users and stakeholders, to be used as input to the development of formal computational models.

Sierhuis, Maarten↗

Comparison of Carbon Dioxide and Helium as Fire Extinguishing Agents for Spacecraft

The effects of radiation heat transfer in microgravity compared to convection heat transfer in earth gravity for opposed-flow (downward) over thermally-thick fuel using low density foam fuel were investigated. Microgravity experiments on flame spread over thermally-thick fuels were conducted using foam fuels to obtain low density and thermal conductivity, and thus large flame spread rate compared to dense fuels such as PMMA. And thereby valid microgravity results were obtained even in 2.2 second drop-tower experiments not to mention for the longer duration tests in Zero Gravity Facility. Contrast to the conventional understanding, it was found that steady flame spread can occur over thick fuels in quiescent microgravity environments, especially when radiatively-active diluent gases such as CO2 were employed. This is proposed to result from radiative heat transfer from the flame to the fuel surface, which could lead to steady spread even when the amount of the heat transfer via conduction from the flame to the fuel bed is negligible. Radiative effects are more significant at microgravity conditions because the flame is thicker and thus the volume of radiating combustion products is larger as well. These results suggested that helium may be a better inert or extinguishment agent on both a mass and a mole bases at microgravity even though CO2 is much better on a mole bases at earth gravity, and these are relevant to studies of fire safety in manned spacecraft, particularly the International Space Station that uses CO2 fire extinguishers. CO2 may not be as effective as an extinguishing agent at g as it is at earth gravity in some conditions because of the differences in spread mechanisms between the two cases. In particular, the difference between conduction-dominated heat transport to the fuel bed at earth gravity and radiation-dominated heat transport at g indicates that radiatively-inert diluent such as helium could be preferable in g applications. Helium may be a superior fire suppression agent at g on several bases. First, helium is more effective than CO2 on a mole basis (thus pressure times storage volume basis) at g, meaning that the size and weight of storage bottles would be smaller for the same fire-fighting capability. Second; helium is much more effective on a mass basis (by about 11 times) at g. Third; helium has no physiological activity, unlike CO2 that affects human respiration. Fourth, as compared to N2 or CO2, is not very soluble in water and thus has fewer tendencies to cause bloodstream bubble formation following rapid spacecraft cabin depressurization.

Gokoglu, Suleyman↗

Comparison of Carbon Dioxide and Helium as Fire Extinguishing Agents for Spacecraft

The effects of radiation heat transfer in microgravity compared to convection heat transfer in earth gravity for opposed-flow (downward) over thermally-thick fuel using low density foam fuel were investigated. Microgravity experiments on flame spread over thermally-thick fuels were conducted using foam fuels to obtain low density and thermal conductivity, and thus large flame spread rate compared to dense fuels such as PMMA. And thereby valid microgravity results were obtained even in 2.2 second drop-tower experiments not to mention for the longer duration tests in Zero Gravity Facility. Contrast to the conventional understanding, it was found that steady flame spread can occur over thick fuels in quiescent microgravity environments, especially when radiatively-active diluent gases such as CO2 were employed. This is proposed to result from radiative heat transfer from the flame to the fuel surface, which could lead to steady spread even when the amount of the heat transfer via conduction from the flame to the fuel bed is negligible. Radiative effects are more significant at microgravity conditions because the flame is thicker and thus the volume of radiating combustion products is larger as well. These results suggested that helium may be a better inert or extinguishment agent on both a mass and a mole bases at microgravity even though CO2 is much better on a mole bases at earth gravity, and these are relevant to studies of fire safety in manned spacecraft, particularly the International Space Station that uses CO2 fire extinguishers. CO2 may not be as effective as an extinguishing agent at microgravity as it is at earth gravity in some conditions because of the differences in spread mechanisms between the two cases. In particular, the difference between conduction-dominated heat transport to the fuel bed at earth gravity and radiation-dominated heat transport at microgravity indicates that radiatively-inert diluent such as helium could be preferable in microgravity applications. Helium may be a superior fire suppression agent at microgravity on several bases. First, helium is more effective than CO2 on a mole basis (thus pressure times storage volume basis) at microgravity, meaning that the size and weight of storage bottles would be smaller for the same fire-fighting capability. Second; helium is much more effective on a mass basis (by about 11 times) at microgravity. Third; helium has no physiological activity, unlike CO2 that affects human respiration. Fourth, as compared to N2 or CO2, is not very soluble in water and thus has fewer tendencies to cause bloodstream bubble formation following rapid spacecraft cabin depressurization.

Gokoglu, Suleyman↗

Laboratory for Atmospheres: 2004 Technical Highlights

The report describes our role in NASA's mission, gives a broad description of our research, and summarizes our scientists' major accomplishments in 2004. The report also contains useful information on human resources, scientific interactions, outreach activities, and the transformation our laboratory has undergone. This report is published in two versions: 1) an abbreviated print version, and 2) an unabridged electronic version at our Laboratory for Atmospheres Web site: http://atmospheres.gsfc.nasa.gov/.

Source record↗

Heart Rhythm Monitoring in the Constellation Lunar and Launch/Landing EVA Suit: Recommendations from an Expert Panel

Currently there are several physiological monitoring requirements for Extravehicular Activity (EVA) in the Human-Systems Interface Requirements (HSIR) document, including continuous heart rhythm monitoring. However, it is not known whether heart rhythm monitoring in the lunar surface space suit is a necessary capability for lunar surface operations or in launch/landing suit the event of a cabin depressurization enroute to or from the moon. Methods: Current US astronaut corps demographic information was provided to an expert panel of cardiovascular medicine experts, including specialists in electrophysiology, exercise physiology, interventional cardiology and arrhythmia. This information included averages for male/female age, body mass index (BMI), blood pressure, cholesterol, inflammatory markers, echocardiogram, ranges for coronary artery calcium (CAC) scores for long duration astronauts, and ranges for heart rate (HR) and metabolic (MET) rates obtained during microgravity and lunar EVA. Results: The panel determined that no uncontrolled hazard was likely to occur in the suit during lunar surface or contingency microgravity ops that would require ECG monitoring in the highly screened US astronaut population. However having the capability for rhythm monitoring inside the vehicle (IVA) was considered critical to manage an astronaut in distress. Discussion: Heart rate (HR) monitoring alone allows effective monitoring of astronaut health and function. Consequently, electrocardiographic (ECG) monitoring capability as a clinical tool is not essential in the lunar or launch/landing space suit. However, the panel considered that rhythm monitoring could be useful in certain clinical situations, it was not considered required for safe operations. Also, lunar vehicles should be required to have ECG monitoring capability with a minimum of 5-lead ECG (derived 12- lead) for IVA medical assessments.

Scheuring, Richard A.↗

The International Lunar Network

A new lunar science flight projects line has been introduced within NASA s Science Mission Directorate's (SMDs) proposed 2009 budget, including two new robotic missions designed to accomplish key scientific objectives and, when possible, provide results useful to the Exploration Systems Mission Directorate (ESMD) and the Space Operations Mission Directorate (SOMD) as those organizations grapple with the challenges of returning humans to the Moon. The first mission in this line will be the Lunar Reconnaissance Orbiter, an ESMD mission that will acquire key information for human return to the moon activities, which will transition after one year of operations to the SMD Lunar Science Program for a 2-year nominal science mission. The second mission, the Lunar Atmosphere and Dust Environment Explorer (LADEE) will be launch in 2011 along with the GRAIL Discovery mission to the moon. The third is delivery of two landed payloads as part of the International Lunar Network (ILN). This flight projects line provides a robust robotic lunar science program for the next 8 years and beyond, complements SMD s initiatives to build a robust lunar science community through R&A lines, and increases international participation in NASA s robotic exploration plans. The International Lunar Network is envisioned as a global lunar geophysical network, which fulfills many of the stated recommendations of the recent National Research Council report on The Scientific Context for Exploration of the Moon [2], but is difficult for any single space agency to accomplish on its own. The ILN would provide the necessary global coverage by involving US and international landed missions as individual nodes working together. Ultimately, this network could comprise 8-10 or more nodes operating simultaneously, while minimizing the required contribution from each space agency. Indian, Russian, Japanese, and British landed missions are currently being formulated and SMD is actively seeking partnership with these and other space agencies to establish the ILN.

Cohen, Barbara A.↗

Supporting Real-Time Operations and Execution through Timeline and Scheduling Aids

Since 2003, the NASA Ames Research Center has been actively involved in researching and advancing the state-of-the-art of planning and scheduling tools for NASA mission operations. Our planning toolkit SPIFe (Scheduling and Planning Interface for Exploration) has supported a variety of missions and field tests, scheduling activities for Mars rovers as well as crew on-board International Space Station and NASA earth analogs. The scheduled plan is the integration of all the activities for the day/s. In turn, the agents (rovers, landers, spaceships, crew) execute from this schedule while the mission support team members (e.g., flight controllers) follow the schedule during execution. Over the last couple of years, our team has begun to research and validate methods that will better support users during realtime operations and execution of scheduled activities. Our team utilizes human-computer interaction principles to research user needs, identify workflow processes, prototype software aids, and user test these. This paper discusses three specific prototypes developed and user tested to support real-time operations: Score Mobile, Playbook, and Mobile Assistant for Task Execution (MATE).

scheduling↗

NASA's Asteroid Redirect Mission: The Boulder Capture Option

NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (approximately 4-10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is examining another option that entails retrieving a boulder (approximately 1-5 m) via robotic manipulators from the surface of a larger (approximately 100+ m) pre-characterized NEA. This option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa's target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU3) by NASA's OSIRIS REx and JAXA's Hayabusa 2 missions is planned to begin in 2018. The boulder option is an extremely large sample‐return mission with the prospect of bringing back many tons of well‐characterized asteroid material to the Earth‐Moon system. The candidate boulder from the target NEA can be selected based on inputs from the world‐wide science community, ensuring that the most scientifically interesting boulder be returned for subsequent sampling. This boulder option for NASA's ARM can leverage knowledge of previously characterized NEAs from prior robotic missions, which provides more certainty of the target NEA's physical characteristics and reduces mission risk. This increases the return on investment for NASA's future activities with respect to science, human exploration, resource utilization, and planetary defense

Abell, Paul A.↗

Pairwise Trajectory Management (PTM): Concept Description and Documentation

Pairwise Trajectory Management (PTM) is an Interval Management (IM) concept that utilizes airborne and ground-based capabilities to enable the implementation of airborne pairwise spacing capabilities in oceanic regions. The goal of PTM is to use airborne surveillance and tools to manage an "at or greater than" inter-aircraft spacing. Due to the accuracy of Automatic Dependent Surveillance-Broadcast (ADS-B) information and the use of airborne spacing guidance, the minimum PTM spacing distance will be less than distances a controller can support with current automation systems that support oceanic operations. Ground tools assist the controller in evaluating the traffic picture and determining appropriate PTM clearances to be issued. Avionics systems provide guidance information that allows the flight crew to conform to the PTM clearance issued by the controller. The combination of a reduced minimum distance and airborne spacing management will increase the capacity and efficiency of aircraft operations at a given altitude or volume of airspace. This document provides an overview of the proposed application, a description of several key scenarios, a high level discussion of expected air and ground equipment and procedure changes, a description of a NASA human-machine interface (HMI) prototype for the flight crew that would support PTM operations, and initial benefits analysis results. Additionally, included as appendices, are the following documents: the PTM Operational Services and Environment Definition (OSED) document and a companion "Future Considerations for the Pairwise Trajectory Management (PTM) Concept: Potential Future Updates for the PTM OSED" paper, a detailed description of the PTM algorithm and PTM Limit Mach rules, initial PTM safety requirements and safety assessment documents, a detailed description of the design, development, and initial evaluations of the proposed flight crew HMI, an overview of the methodology and results of PTM pilot training requirements focus group and human-in-the-loop testing activities, and the PTM Pilot Guide.

Jones, Kenneth M.↗

NASA’s Interest in 3GPP Mobile Telecommunications Protocols for Near Earth Space and the Lunar Surface

In the next several years, NASA intends to return astronauts to the Moon through the Artemis Program. Under Artemis, NASA plans to collaborate with commercial and international partners to establish a long-term presence on the Moon. Near-term Artemis missions will be analogous but much more sophisticated versions of the last couple of Apollo missions. For example, the first area expected to be explored by an Artemis mission is near the south pole as opposed to the mid-latitudes visited by the Apollo astronauts, which makes direct communications with Earth more complicated. Lunar infrastructure will eventually be built over time by many organizations, public and private, to support sustained human exploration, science, and industrial activities on the Moon. A robust lunar communications and navigation infrastructure will be essential to realizing this long-term vision. Meanwhile, on Earth, major advances are being made as5G mobile telecommunications rollout across the globe. Furthermore, the 3rdGeneration Partnership Project (3GPP) is beginning to define future 6G capabilities. NASA envisions a lunar communications and navigation network with capabilities similar to those of communication networks we enjoy here on Earth. Building such a network will require participation by many organizations. NASA’s Tipping Point program seeks industry-developed space technologies that can both foster commercial space capabilities and benefit future NASA missions. This paper provides an overview of NASA’s interest in 3GPPanddescribescurrent work based on 3GPP standards within NASA or funded by NASA, such as Nokia’s upcoming Tipping Point demonstration of 4G/LTE on the lunar surface in early 2023.

Bernard L Edwards↗

3GPP Telecommunications Technology on the Moon

Under NASA’s Artemis program, NASA is planning to send astronauts back to the Moon in the next couple of years. Near term missions will be analogous but much more sophisticated versions of the last couple of Apollo missions. However, unlike Apollo, this time NASA intends to put the infrastructure in place to support long term human presence and eventual industrialization of the Moon. To make this vision a reality, NASA plans to collaborate with commercial and international partners as much as possible as opposed to developing, building, and operating equipment on its own. Lunar infrastructure will eventually be built over time by many organizations, public and private, to support sustained human exploration, science, and industrial activities. Obviously, this vision for the future will be impossible without a robust lunar communications and navigation system that can support many users with varying degrees of services. On Earth, most people are very familiar with the 3rd Generation Partnership Project (3GPP) 5G mobile telecommunications technology. NASA’s Space Technology Mission Directorate and NASA’s Space Communications and Navigation office would like to see a lunar communications and navigation network with similar capabilities to the cellular communication networks most of us enjoy today. Building such a network will require participation by many organizations. This paper will provide an overview of NASA’s interest in using 5G and beyond on the lunar surface; it will also describe current work based on 3GPP standards within NASA or funded by NASA, such as Nokia’s upcoming Tipping Point demonstration of 4G / LTE on the lunar surface.

Bernard Edwards↗

A Decision Support System for Extravehicular Operations Under Significant Communication Latency

Within the next few decades, humanity hopes to perform extravehicular activities (EVAs) on the surface of Mars; however, several technical and operational challenges must first be overcome. Foremost among these challenges is managing a significant two-way communication latency between Earth and Mars. Current and historical paradigms of EVA operations have required near-real-time communication between the crewmember(s) performing an EVA and an Earth-based mission control. Next-generation operational paradigms for supporting deep space exploration will necessitate a distributed decision authority system, including delayed Earth-based mission control, the on-planet extravehicular crewmember(s), and intermediate mission support from intravehicular crewmember(s) within real-time communication range. This latter group is of particular interest: they must provide operations support without the plentiful resources available to mission control on Earth. For this purpose, NASA is developing the Personalized EVA Informatics and Decision Support (PersEIDS) software platform. PersEIDS is designed to bolster operator situational awareness and offload operator workload by automating the tracking and projection of consumables usage over an EVA timeline, providing real-time probabilistic safety assessments of an EVA timeline given consumables constraints, and recommending alternative EVA timeline(s) when the active timeline is not expected to be completed under consumables limits. The PersEIDS concept of operations, use cases, and models will be presented. A limited version of PersEIDS was demonstrated during a three-day-long study where each day a roughly four-hour-long simulated Martian EVA was performed in virtual reality at the NASA Johnson Space Center. The first day was a control trial without PersEIDS support; the second and third days represented different levels of decision support provided by PersEIDS to the intravehicular crewmember acting as mission control. With PersEIDS support, the IV crewmember was able to manage the mission to completion faster and with more remaining consumables; however, additional testing is required to understand confounding factors, e.g. training bias.

Mars↗

Study of Pairwise Deconfliction Metrics to Analyze Air Traffic Complexity in Upper Class E Airspace

Upper Class E Traffic Management (ETM) is envisioned to cooperatively facilitate operations of a diverse set of aerial vehicles, such as high-altitude long-endurance fixed-wing unmanned aircraft (low-speed and high-speed), high-altitude platforms, airships, stratospheric balloons, supersonic unmanned and commercial aircraft, etc., with a wide variety of mission types, performance characteristics, communication, navigation and surveillance capabilities, maneuverability, and on-board avionics in the National Airspace System (NAS) ’above’ 60,000 feet above mean sea level, without an active and direct control from human air traffic controllers. A diverse mixture of aerial vehicle types creates significant challenges in understanding air traffic complexity, which may not correlate strongly with air traffic density. One key step for determining air traffic complexity in upper class E airspace is to first understand pairwise deconfliction metrics such as reachability, reserve area, and reserve flight time for each pair of unique aerial vehicle types under potential conflict. Therefore, pairwise deconfliction metrics are first defined, and analytical equations are derived for conflict resolution using the heading change maneuver. Next, case studies are performed to analyze deconfliction metrics to avoid secondary conflicts in upper class E airspace. The study shows that pairwise deconfliction metrics are functions of maneuverability, performance characteristics, uncertainty in position and velocity, heading angle change, and conflict angle of aerial vehicles. The next step for this research is to build a mathematical model for air traffic complexity using pairwise deconfliction metrics and validate it in an upper Class E simulation environment.

Airspace Complexity↗

Study of Pairwise Deconfliction Metrics to Analyze Air Traffic Complexity in Upper Class E Airspace

Upper Class E Traffic Management (ETM) is envisioned to cooperatively facilitate operations of a diverse set of aerial vehicles, such as high-altitude long-endurance fixed-wing unmanned aircraft (low-speed and high-speed), high-altitude platforms, airships, stratospheric balloons, supersonic unmanned and commercial aircraft, etc., with a wide variety of mission types, performance characteristics, communication, navigation and surveillance capabilities, maneuverability, and on-board avionics in the National Airspace System (NAS) ’above’ 60,000 feet above mean sea level, without an active and direct control from human air traffic controllers. A diverse mixture of aerial vehicle types creates significant challenges in understanding air traffic complexity, which may not correlate strongly with air traffic density. One key step for determining air traffic complexity in upper class E airspace is to first understand pairwise deconfliction metrics such as reachability, reserve area, and reserve flight time for each pair of unique aerial vehicle types under potential conflict. Therefore, pairwise deconfliction metrics are first defined, and analytical equations are derived for conflict resolution using the heading change maneuver. Next, case studies are performed to analyze deconfliction metrics to avoid secondary conflicts in upper class E airspace. The study shows that pairwise deconfliction metrics are functions of maneuverability, performance characteristics, uncertainty in position and velocity, heading angle change, and conflict angle of aerial vehicles. The next step for this research is to build a mathematical model for air traffic complexity using pairwise deconfliction metrics and validate it in an upper Class E simulation environment.

Airspace Complexity↗

A Decision Support System for Extravehicular Operations Under Significant Communication Latency

Humanity hopes to perform extravehicular activities (EVAs) on the surface of Mars; however, several technical and operational challenges must first be overcome. Foremost among these challenges is managing a significant communication latency between Earth and Mars. Current and historical paradigms of EVA operations have required near-real-time communication between the crewmember(s) and Earth-based mission control. Nextgeneration operational paradigms for supporting deep space exploration will necessitate a distributed decision authority system, including delayed Earth-based mission control, the onplanet extravehicular crewmember(s), and intermediate mission support from intravehicular (IV) crewmember(s) within real-time communication range. This latter group is of particular interest: they must provide operations support without the plentiful resources available to mission control on Earth. Thus, NASA is developing the Personalized EVA Informatics and Decision Support (PersEIDS) software platform. PersEIDS is designed to bolster operator situational awareness and offload operator workload by automatically tracking and projecting consumables usage over an EVA timeline, providing real-time probabilistic safety assessments and recommending alternative EVA timeline(s) when the active timeline is not expected to be completed under consumables limits. The PersEIDS concept of operations, use cases, and models will be presented. A limited version of PersEIDS was demonstrated during a three-day-long study where each day a roughly four-hour-long simulated Martian EVA was performed in virtual reality at the NASA Johnson Space Center. The first day was a control trial without PersEIDS support; the second and third days represented different levels of decision support provided by PersEIDS to the IV crewmember acting as mission control. With PersEIDS support, the IV crewmember was able to manage the mission to completion faster and with more remaining consumables; however, additional testing is required to understand confounding factors, e.g., training bias.

Mars↗