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NASA NTRS2010

Relationships Among Lower Body Strength, Power, and Performance of Functional Tasks

There is a large degree of variability among crewmembers with respect to decrements in muscle strength and power following long duration spaceflight, ranging from 0 to approx.30% reductions. The purpose of this study was to investigate the influence of varying decrements in lower body muscle strength and power (relative to body weight) on the performance of 2 occupationally relevant tasks (ladder climb and supine egress & walk). Seventeen participants with leg strength similar to US crewmembers performed a leg press power test, an isokinetic knee extension strength test and they were asked to complete the 2 functional tasks as quickly as possible. On additional test days the participants were asked to repeat the functional tasks under 3 conditions where a different external load was applied each time using a weighted suit in order to experimentally manipulate participants strength/body weight and power/body weight ratios. The weight in the suit ranged from 20-120% of body weight and was distributed in proportion to limb segment weights to minimize changes in center of gravity. The ladder task consisted of climbing 40 rungs on a ladder treadmill as fast as possible. The supine egress & walk task consisted of rising from a supine position and walking through an obstacle course. Results show a relatively linear relationship between strength/body weight and task time and power/body weight with task time such that the fastest performance times are associated with higher strength and power with about half the variance in task time is accounted for by a single variable (either strength or power). For the average person, a 20% reduction in power/body weight (from 18 to 14.4 W/kg) induces an increase (slowing) of about 10 seconds in the ladder climb task from 14 to 24 seconds (approx.70%) and a slowing of the supine egress & walk task from 14 to 21 seconds (approx.50%). Similar relationships were observed with strength/body weight and task performance. For the average person, a 20% reduction in strength/body weight (from 2.1 to 1.7 Nm/kg) resulted in a slowing of the ladder climb from 10.5 to 24 seconds (approx.128%) and a slowing of the supine egress & walk from 11 to 20 seconds (approx.82%). These data suggest that the single variable of either low body muscle strength or power, relative to body weight is predictive of about 50% of the variance in task performance time, and that considerable slowing in task performance is associated with relatively typical decrements in muscle performance seen with long duration spaceflight. The observation of a relatively linear relationship between strength/power and task time suggests that across the full spectrum of initial crew strengths and typical decrements in strength previously observed, that task performance would be expected to be slowed following long duration spaceflight. These data will be confirmed in actual spaceflight with subsequent studies.

Ploutz-Snyder, Lori↗

NASA NTRS2010

Spheres of Earth: An Introduction to Making Observations of Earth Using an Earth System's Science Approach. Student Guide

Scientists from the Image Science and Analysis Laboratory (ISAL) at NASA's Johnson Space Center (JSC) work with astronauts onboard the International Space Station (ISS) who take images of Earth. Astronaut photographs, sometimes referred to as Crew Earth Observations, are taken using hand-held digital cameras onboard the ISS. These digital images allow scientists to study our Earth from the unique perspective of space. Astronauts have taken images of Earth since the 1960s. There is a database of over 900,000 astronaut photographs available at http://eol.jsc.nasa.gov . Images are requested by ISAL scientists at JSC and astronauts in space personally frame and acquire them from the Destiny Laboratory or other windows in the ISS. By having astronauts take images, they can specifically frame them according to a given request and need. For example, they can choose to use different lenses to vary the amount of area (field of view) an image will cover. Images can be taken at different times of the day which allows different lighting conditions to bring out or highlight certain features. The viewing angle at which an image is acquired can also be varied to show the same area from different perspectives. Pointing the camera straight down gives you a nadir shot. Pointing the camera at an angle to get a view across an area would be considered an oblique shot. Being able to change these variables makes astronaut photographs a unique and useful data set. Astronaut photographs are taken from the ISS from altitudes of 300 - 400 km (~185 to 250 miles). One of the current cameras being used, the Nikon D3X digital camera, can take images using a 50, 100, 250, 400 or 800mm lens. These different lenses allow for a wider or narrower field of view. The higher the focal length (800mm for example) the narrower the field of view (less area will be covered). Higher focal lengths also show greater detail of the area on the surface being imaged. Scientists from the Image Science and Analysis Laboratory (ISAL) at NASA s Johnson Space Center (JSC) work with astronauts onboard the International Space Station (ISS) who take images of Earth. Astronaut photographs, sometimes referred to as Crew Earth Observations, are taken using hand-held digital cameras onboard the ISS. These digital images allow scientists to study our Earth from the unique perspective of space. Astronauts have taken images of Earth since the 1960s. There is a database of over 900,000 astronaut photographs available at http://eol.jsc.nasa.gov . Images are requested by ISAL scientists at JSC and astronauts in space personally frame and acquire them from the Destiny Laboratory or other windows in the ISS. By having astronauts take images, they can specifically frame them according to a given request and need. For example, they can choose to use different lenses to vary the amount of area (field of view) an image will cover. Images can be taken at different times of the day which allows different lighting conditions to bring out or highlight certain features. The viewing angle at which an image is acquired can also be varied to show the same area from different perspectives. Pointing the camera straight down gives you a nadir shot. Pointing the camera at an angle to get a view across an area would be considered an oblique shot. Being able to change these variables makes astronaut photographs a unique and useful data set. Astronaut photographs are taken from the ISS from altitudes of 300 - 400 km (approx.185 to 250 miles). One of the current cameras being used, the Nikon D3X digital camera, can take images using a 50, 100, 250, 400 or 800mm lens. These different lenses allow for a wider or narrower field of view. The higher the focal length (800mm for example) the narrower the field of view (less area will be covered). Higher focal lengths also show greater detail of the area on the surface being imaged. There are four major systems or spheres of Earth. They are: Atmosphere, Biosphere, Hydrosphe, and Litho/Geosphere.

Graff, Paige Valderrama↗

NASA NTRS2010

Behavioral Issues Associated With Long Duration Space Expeditions: Review and Analysis of Astronaut Journals

Personal journals maintained by NASA astronauts during six-month expeditions onboard the International Space Station were analyzed to obtain information concerning a wide range of behavioral and human factors issues. Astronauts wrote most about their work, followed by outside communications (with mission control, family, and friends), adjustment to the conditions, interactions with crew mates, recreation/leisure, equipment (installation, maintenance), events (launches, docking, hurricanes, etc.), organization/management, sleep, and food. The study found evidence of a decline in morale during the third quarters of the missions and identified key factors that contribute to sustained adjustment and optimal performance during long-duration space expeditions. Astronauts reported that they benefited personally from writing in their journals because it helped maintain perspective on their work and relations with others. Responses to questions asked before, during, and after the expeditions show that living and working onboard the ISS is not as difficult as the astronauts anticipate before starting their six-month tours of duty. Recommendations include application of study results and continuation of the experiment to obtain additional data as crew size increases and operations evolve.

Struster, Jack↗

NASA NTRS2010

Asbestos Exposure Assessment Database

Exposure to particular hazardous materials in a work environment is dangerous to the employees who work directly with or around the materials as well as those who come in contact with them indirectly. In order to maintain a national standard for safe working environments and protect worker health, the Occupational Safety and Health Administration (OSHA) has set forth numerous precautionary regulations. NASA has been proactive in adhering to these regulations by implementing standards which are often stricter than regulation limits and administering frequent health risk assessments. The primary objective of this project is to create the infrastructure for an Asbestos Exposure Assessment Database specific to NASA Johnson Space Center (JSC) which will compile all of the exposure assessment data into a well-organized, navigable format. The data includes Sample Types, Samples Durations, Crafts of those from whom samples were collected, Job Performance Requirements (JPR) numbers, Phased Contrast Microscopy (PCM) and Transmission Electron Microscopy (TEM) results and qualifiers, Personal Protective Equipment (PPE), and names of industrial hygienists who performed the monitoring. This database will allow NASA to provide OSHA with specific information demonstrating that JSC s work procedures are protective enough to minimize the risk of future disease from the exposures. The data has been collected by the NASA contractors Computer Sciences Corporation (CSC) and Wyle Laboratories. The personal exposure samples were collected from devices worn by laborers working at JSC and by building occupants located in asbestos-containing buildings.

Arcot, Divya K.↗

NASA NTRS2010

Automating the Generation of the Cassini Tour Atlas Database

The Tour Atlas is a large database of geometrical tables, plots, and graphics used by Cassini science planning engineers and scientists primarily for science observation planning. Over time, as the contents of the Tour Atlas grew, the amount of time it took to recreate the Tour Atlas similarly grew--to the point that it took one person a week of effort. When Cassini tour designers estimated that they were going to create approximately 30 candidate Extended Mission trajectories--which needed to be analyzed for science return in a short amount of time--it became a necessity to automate. We report on the automation methodology that reduced the amount of time it took one person to (re)generate a Tour Atlas from a week to, literally, one UNIX command.

Cassini↗

NASA NTRS2010

The ICARE Method

The ICARE method is a flexible, widely applicable method for systems engineers to solve problems and resolve issues in a complete and comprehensive manner. The method can be tailored by diverse users for direct application to their function (e.g. system integrators, design engineers, technical discipline leads, analysts, etc.). The clever acronym, ICARE, instills the attitude of accountability, safety, technical rigor and engagement in the problem resolution: Identify, Communicate, Assess, Report, Execute (ICARE). This method was developed through observation of Space Shuttle Propulsion Systems Engineering and Integration (PSE&I) office personnel approach in an attempt to succinctly describe the actions of an effective systems engineer. Additionally it evolved from an effort to make a broadly-defined checklist for a PSE&I worker to perform their responsibilities in an iterative and recursive manner. The National Aeronautics and Space Administration (NASA) Systems Engineering Handbook states, engineering of NASA systems requires a systematic and disciplined set of processes that are applied recursively and iteratively for the design, development, operation, maintenance, and closeout of systems throughout the life cycle of the programs and projects. ICARE is a method that can be applied within the boundaries and requirements of NASA s systems engineering set of processes to provide an elevated sense of duty and responsibility to crew and vehicle safety. The importance of a disciplined set of processes and a safety-conscious mindset increases with the complexity of the system. Moreover, the larger the system and the larger the workforce, the more important it is to encourage the usage of the ICARE method as widely as possible. According to the NASA Systems Engineering Handbook, elements of a system can include people, hardware, software, facilities, policies and documents; all things required to produce system-level results, qualities, properties, characteristics, functions, behavior and performance. The ICARE method can be used to improve all elements of a system and, consequently, the system-level functional, physical and operational performance. Even though ICARE was specifically designed for a systems engineer, any person whose job is to examine another person, product, or process can use the ICARE method to improve effectiveness, implementation, usefulness, value, capability, efficiency, integration, design, and/or marketability. This paper provides the details of the ICARE method, emphasizing the method s application to systems engineering. In addition, a sample of other, non-systems engineering applications are briefly discussed to demonstrate how ICARE can be tailored to a variety of diverse jobs (from project management to parenting).

Henke, Luke↗

NASA NTRS2001

NASA Tech Briefs, February 2001

The topics include: 1) Application Briefs; 2) National Design Engineering Show Preview; 3) Marketing Inventions to Increase Income; 4) A Personal-Computer-Based Physiological Training System; 5) Reconfigurable Arrays of Transistors for Evolvable Hardware; 6) Active Tactile Display Device for Reading by a Blind Person; 7) Program Automates Management of IBM VM Computer Systems; 8) System for Monitoring the Environment of a Spacecraft Launch; 9) Measurement of Stresses and Strains in Muscles and Tendons; 10) Optical Measurement of Temperatures in Muscles and Tendons; 11) Small Low-Temperature Thermometer With Nanokelvin Resolution; 12) Heterodyne Interferometer With Phase-Modulated Carrier; 13) Rechargeable Batteries Based on Intercalation in Graphite; 14) Signal Processor for Doppler Measurements in Icing Research; 15) Model Optimizes Drying of Wet Sheets; 16) High-Performance POSS-Modified Polymeric Composites; 17) Model Simulates Semi-Solid Material Processing; 18) Modular Cryogenic Insulation; 19) Passive Venting for Alleviating Helicopter Tail-Boom Loads; 20) Computer Program Predicts Rocket Noise; 21) Process for Polishing Bare Aluminum to High Optical Quality; 22) External Adhesive Pressure-Wall Patch; 23) Java Implementation of Information-Sharing Protocol; 24) Electronic Bulletin Board Publishes Schedules in Real Time; 25) Apparatus Would Extract Water From the Martian Atmosphere; 26) Review of Research on Supercritical vs Subcritical Fluids; 27) Hybrid Regenerative Water-Recycling System; 28) Study of Fusion-Driven Plasma Thruster With Magnetic Nozzle; 29) Liquid/Vapor-Hydrazine Thruster Would Produce Small Impulses; and 30) Thruster Based on Sublimation of Solid Hydrazine

Source record↗

NASA NTRS2011

AstroBetter: A Blog and Wiki for Professional Astronomers

AstroBetter.com is a multi-contributor blog and wiki website designed for information sharing among professional astronomers. The goal of the site is to increase the productivity of astronomers by creating a centralized location for tips and tools of our multifaceted trade. Our content includes topics related to data reduction and analysis, general computing, writing papers and proposals, giving talks, teaching, career planning, productivity, organization, and diversity and equity in science and education. While we have several contributors, the site is intended to be community driven and we encourage everyone to publish to the wiki, submit guest posts, suggest post ideas, and to comment on blog entries. One of our primary goals is to consolidate and reduce the transient nature of the astronomy community's collective knowledge base by having an active wiki. Currently, the most common way to share astro-centric tools and tips that are not appropriate for a published paper, is to put them on an individual's website. However, the average astronomer's website will have at least four different addresses over the course of their career and only the site owner can edit the content. As a result, information on personal websites goes stale very quickly and deal links to such sites abound. It is our hope that community maintained wikis, such as the one hosted on AstroBetter, will gradually replace the personal website. In this poster we introduce the contributors to AstroBetter, show statistics about our current readership, give excerpts of some of our most popular posts and wiki entries, and show how anyone can add or edit content on the wiki. The goal of this poster is to spread the work about AstroBetter and increase our community of readers and wiki editors, because together, we can AstroBetter.

Rigby, Jane↗

NASA NTRS1999

Interoperability Trends in Extravehicular Activity (EVA) Space Operations for the 21st Century

No other space operations in the 21 st century more comprehensively embody the challenges and dependencies of interoperability than EVA. This discipline is already functioning at an W1paralleled level of interagency, inter-organizational and international cooperation. This trend will only increase as space programs endeavor to expand in the face of shrinking budgets. Among the topics examined in this paper are hardware-oriented issues. Differences in design standards among various space participants dictate differences in the EVA tools that must be manufactured, flown and maintained on-orbit. Presently only two types of functional space suits exist in the world. However, three versions of functional airlocks are in operation. Of the three airlocks, only the International Space Station (ISS) Joint Airlock can accommodate both types of suits. Due to functional differences in the suits, completely different operating protocols are required for each. Should additional space suit or airlock designs become available, the complexity will increase. The lessons learned as a result of designing and operating within such a system are explored. This paper also examines the non-hardware challenges presented by interoperability for a discipline that is as uniquely dependent upon the individual as EVA. Operation of space suits (essentially single-person spacecrafts) by persons whose native language is not that of the suits' designers is explored. The intricacies of shared mission planning, shared control and shared execution of joint EVA's are explained. For example, once ISS is fully functional, the potential exists for two crewmembers of different nationality to be wearing suits manufactured and controlled by a third nation, while operating within an airlock manufactured and controlled by a fourth nation, in an effort to perform tasks upon hardware belonging to a fifth nation. Everything from training issues, to procedures development and writing, to real-time operations is addressed. Finally, this paper looks to the management challenges presented by interoperability in general. With budgets being reduced among all space-faring nations, the need to expand cooperation in the highly expensive field of human space operations is only going to intensify. The question facing management is not if the trend toward interoperation will continue, but how to best facilitate its doing so. Real-world EVA interoperability experience throughout the ShuttlelMir and ISS Programs is discussed to illustrate the challenges and

Miller, Gerald E.↗

NASA NTRS2006

Secure Display of Space-Exploration Images

Java EDR Display Interface (JEDI) is software for either local display or secure Internet distribution, to authorized clients, of image data acquired from cameras aboard spacecraft engaged in exploration of remote planets. ( EDR signifies experimental data record, which, in effect, signifies image data.) Processed at NASA s Multimission Image Processing Laboratory (MIPL), the data can be from either near-realtime processing streams or stored files. JEDI uses the Java Advanced Imaging application program interface, plus input/output packages that are parts of the Video Image Communication and Retrieval software of the MIPL, to display images. JEDI can be run as either a standalone application program or within a Web browser as a servlet with an applet front end. In either operating mode, JEDI communicates using the HTTP(s) protocol(s). In the Web-browser case, the user must provide a password to gain access. For each user and/or image data type, there is a configuration file, called a "personality file," containing parameters that control the layout of the displays and the information to be included in them. Once JEDI has accepted the user s password, it processes the requested EDR (provided that user is authorized to receive the specific EDR) to create a display according to the user s personality file.

Cheng, Cecilia↗

NASA NTRS2011

Characterization of Volume F Trash from Four Recent STS Missions: Microbial Occurrence, Numbers, and Identifications

The fate of space-generated solid wastes, including trash, for future missions is under consideration by NASA. Several potential treatment options are under active technology development. Potential fates for space-generated solid wastes: Storage without treatment; storage after treatment(s) including volume reduction, water recovery, sterilization, and recovery plus recycling of waste materials. For this study, a microbial characterization was made on trash returned from four recent STS missions. The material analyzed were 'Volume F' trash and other bags of accompanying trash. This is the second of two submitted papers on these wastes. This first one covered trash content, weight and water content. Upon receipt, usually within 2 days of landing, trash contents were catalogued and placed into categories: drink containers, food waste, personal hygiene items, and packaging materials, i.e., plastic film and duct tape. Microbial counts were obtained with cultivatable counts on agar media and direct counts using Acridine Orange fluorescent stain (AODC). Trash bag surfaces, 25 square cm , were also sampled. Direct counts were approximately 1 x 10(exp 6) microbes/square cm and cultivatable counts ranged from 1 x 10 to 1 X 10(exp 4) microbes/ square cm-2. Aerobic microbes, aerobic sporeformers, and yeasts plus molds were common for all four missions. Waste items from each category were placed into sterile ziplock bags and 1.5 L sterile DI water added. These were then dispersed by hand shaking for 2 min. prior to inoculation of count media or determining AODC. In general, cultivatable microbes were found in drinks, food wastes, and personal hygiene items. Direct counts were usually higher than cultivatable counts. Some pathogens were found: Staphylococcus auerus, Escherichia coli (fecal wastes). Count ranges: drink pouches - AODC 2 x 10(exp 6) to 1 X 10(exp 8) g(sub fw) (exp -1); cultivatable counts variable between missions; food wastes: Direct counts were close to aerobic plate counts. Counts ranged from 10(exp 6) to 10(exp 9) per g(sub fw). Identities of isolates from cultivation media were obtained using a Biolog Microbial ID System or microSEQ molecular ID methodology using an ABI3130 gene analyzer.

Strayer, Richard F.↗

NASA NTRS2011

Characterization of Volume F Trash from Four Recent STS Missions: Weights, Categorization, Water Content

The fate of space-generated solid wastes, including trash, for future missions is under consideration by NASA. Several potential treatment options are under consideration and active technology development. Potential fates for space-generated solid wastes are: Storage without treatment; storage after treatment(s) including volume reduction, water recovery, sterilization, and recovery plus recycling of waste materials. Recycling might be important for partial or full closure scenarios because of the prohibitive costs associated with resupply of consumable materials. For this study, we determined the composition of trash returned from four recent STS missions. The trash material was 'Volume F' trash and other trash, in large zip-lock bags, that accompanied the Volume F trash. This is the first of two submitted papers on these wastes. This one will cover trash content, weight and water content. The other will report on the microbial Characterization of this trash. STS trash was usually made available within 2 days of landing at KSC. The Volume F bag was weighed, opened and the contents were catalogued and placed into one of the following categories: food waste (and containers), drink containers, personal hygiene items - including EVA maximum absorbent garments (MAGs)and Elbow packs (daily toilet wipes, etc), paper, and packaging materials - plastic firm and duct tape. Trash generation rates for the four STS missions: Total wet trash was 0.602 plus or minus 0.089 kg(sub wet) crew(sup -1) d(sup -1) containing about 25% water at 0.154 plus or minus 0.030 kg(sub water) crew(sup -1) d(sup -1) (avg plus or minus stdev). Cataloguing by category: personal hygiene wastes accounted for 50% of the total trash and 69% of the total water for the four missions; drink items were 16% of total weight and 16% water; food wastes were 22% of total weight and 15% of the water; office waste and plastic film were 2% and 11% of the total waste and did not contain any water. The results can be used by NASA to determine requirements and criteria for Waste Management Systems on future missions.

Strayer, Richard F.↗

NASA NTRS2005

Encryption for Remote Control via Internet or Intranet

A data-communication protocol has been devised to enable secure, reliable remote control of processes and equipment via a collision-based network, while using minimal bandwidth and computation. The network could be the Internet or an intranet. Control is made secure by use of both a password and a dynamic key, which is sent transparently to a remote user by the controlled computer (that is, the computer, located at the site of the equipment or process to be controlled, that exerts direct control over the process). The protocol functions in the presence of network latency, overcomes errors caused by missed dynamic keys, and defeats attempts by unauthorized remote users to gain control. The protocol is not suitable for real-time control, but is well suited for applications in which control latencies up to about 0.5 second are acceptable. The encryption scheme involves the use of both a dynamic and a private key, without any additional overhead that would degrade performance. The dynamic key is embedded in the equipment- or process-monitor data packets sent out by the controlled computer: in other words, the dynamic key is a subset of the data in each such data packet. The controlled computer maintains a history of the last 3 to 5 data packets for use in decrypting incoming control commands. In addition, the controlled computer records a private key (password) that is given to the remote computer. The encrypted incoming command is permuted by both the dynamic and private key. A person who records the command data in a given packet for hostile purposes cannot use that packet after the public key expires (typically within 3 seconds). Even a person in possession of an unauthorized copy of the command/remote-display software cannot use that software in the absence of the password. The use of a dynamic key embedded in the outgoing data makes the central-processing unit overhead very small. The use of a National Instruments DataSocket(TradeMark) (or equivalent) protocol or the User Datagram Protocol makes it possible to obtain reasonably short response times: Typical response times in event-driven control, using packets sized .300 bytes, are <0.2 second for commands issued from locations anywhere on Earth. The protocol requires that control commands represent absolute values of controlled parameters (e.g., a specified temperature), as distinguished from changes in values of controlled parameters (e.g., a specified increment of temperature). Each command is issued three or more times to ensure delivery in crowded networks. The use of absolute-value commands prevents additional (redundant) commands from causing trouble. Because a remote controlling computer receives "talkback" in the form of data packets from the controlled computer, typically within a time interval < or =1 s, the controlling computer can re-issue a command if network failure has occurred. The controlled computer, the process or equipment that it controls, and any human operator(s) at the site of the controlled equipment or process should be equipped with safety measures to prevent damage to equipment or injury to humans. These features could be a combination of software, external hardware, and intervention by the human operator(s). The protocol is not fail-safe, but by adopting these safety measures as part of the protocol, one makes the protocol a robust means of controlling remote processes and equipment by use of typical office computers via intranets and/or the Internet.

Lineberger, Lewis↗

NASA NTRS2011

Constellation Program Lessons Learned: Detailed Lessons Learned - Volume 2

These lessons learned are part of a suite of hardware, software, test results, designs, knowledge base, and documentation that comprises the legacy of the Constellation Program. The context, summary information, and lessons learned are presented in a factual format, as known and described at the time. While our opinions might be discernable in the context, we have avoided all but factually sustainable statements. Statements should not be viewed as being either positive or negative; their value lies in what we did and what we learned that is worthy of passing on. The lessons include both "dos" and "don ts." In many cases, one person s "do" can be viewed as another person s "don t"; therefore, we have attempted to capture both perspectives when applicable and useful. While Volume I summarizes the views of those who managed the program, this Volume II encompasses the views at the working level, describing how the program challenges manifested in day-to-day activities. Here we see themes that were perhaps hinted at, but not completely addressed, in Volume I: unintended consequences of policies that worked well at higher levels but lacked proper implementation at the working level; long-term effects of the "generation gap" in human space flight development, the need to demonstrate early successes at the expense of thorough planning, and the consequences of problems and challenges not yet addressed because other problems and challenges were more immediate or manifest. Not all lessons learned have the benefit of being operationally vetted, since the program was cancelled shortly after Preliminary Design Review. We avoid making statements about operational consequences (with the exception of testing and test flights that did occur), but we do attempt to provide insight into how operational thinking influenced design and testing. The lessons have been formatted with a description, along with supporting information, a succinct statement of the lesson learned, and recommendations for future programs and projects that may be placed in similar circumstances.

Jennifer Rhatigan↗

NASA NTRS2011

Determining postural stability

A method for determining postural stability of a person can include acquiring a plurality of pressure data points over a period of time from at least one pressure sensor. The method can also include the step of identifying a postural state for each pressure data point to generate a plurality of postural states. The method can include the step of determining a postural state of the person at a point in time based on at least the plurality of postural states.

Lieberman, Erez↗

NASA NTRS2011

What Threats to Human Health Does Space Radiation Pose in Orbit

The Space Shuttle program spanned more than the entire length of a solar cycle. Investigations aimed towards understanding the health risks of the astronauts from exposures to space radiation involved mostly physical measurements of the dose and the linear energy transfer (LET) spectrum. Measurement of the dose rate on the Shuttle provided invariable new data for different periods of the solar cycle, whereas measurement of the LET spectrum using the tissue equivalent proportional counter (TEPC) produced the most complete mapping of the radiation environment of the low Earth orbits (LEO). Exposures to the Shuttle astronauts were measured by the personal dosimeter worn by the crewmembers. Analysis of over 300 personal dosimeter readings indicated a dependence on the mission duration, the altitude and inclination of the orbit, and the solar cycle, with the crewmembers on the launch and repair of the Hubble telescope receiving the highest doses due to the altitude of the mission. Secondary neutrons inside the Shuttle were determined by recoil protons or with Bonner spheres, and may contribute significantly to the risks of the crewmembers. In addition, the skin dose and the doses received at different organs were compared using a human phantom onboard a Shuttle mission. A number of radiobiology investigations wer e also performed. The biological doses were determined on six astronauts/cosmonauts on long-duration Shuttle/Mir missions and on two crewmembers on a Hubble repair mission by analyzing the damages in the chromosomes of the crewmembers? white blood cells. Several experiments were also conducted to address the question of possible synergistic effects of spaceflight, microgravity in particular, on the repair of radiation-induced DNA damages. The experimental design included exposure of cells before launch, during flight, or after landing. These physical and biological studies were invaluable in predicting the health risks for astronauts on ISS and future exploration missions. Educational Objectives: A group of high school students flew color negative films on tw o Shuttle missions to detect the radiation environment in orbit. This and other experiments onboard of the Shuttle were aimed at educating the general public of the space program.

Wu, Honglu↗

NASA NTRS2005

Multistage Magnetic Separator of Cells and Proteins

The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to position the capture magnet above the upper cuvette into which a fraction of the sample is collected. The electronic unit includes a power switch, power-supply circuitry that accepts 110-Vac input power, an RS-232 interface, and status lights. The personal computer runs the MAGSEP software and controls the operation of the MAGSEP through the RS-232 interface. The status of the power, the translating electromagnet, the capture magnet, and the rotation of the upper plate are indicated in a graphical user interface on the computer screen.

Barton, Ken↗

NASA NTRS2005

Program Predicts Time Courses of Human/Computer Interactions

CPM X is a computer program that predicts sequences of, and amounts of time taken by, routine actions performed by a skilled person performing a task. Unlike programs that simulate the interaction of the person with the task environment, CPM X predicts the time course of events as consequences of encoded constraints on human behavior. The constraints determine which cognitive and environmental processes can occur simultaneously and which have sequential dependencies. The input to CPM X comprises (1) a description of a task and strategy in a hierarchical description language and (2) a description of architectural constraints in the form of rules governing interactions of fundamental cognitive, perceptual, and motor operations. The output of CPM X is a Program Evaluation Review Technique (PERT) chart that presents a schedule of predicted cognitive, motor, and perceptual operators interacting with a task environment. The CPM X program allows direct, a priori prediction of skilled user performance on complex human-machine systems, providing a way to assess critical interfaces before they are deployed in mission contexts.

Vera, Alonso↗