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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Investigations of thermal control for extravehicular space suits are reported. The characteristics of independent cooling of temperature and removal of excess heat from separate regions of the body, and the applications of heat pipes in protective suits are discussed along with modeling of the human thermal system.
Shoulder and hip joints for hard space suits are disclosed which are comprised of three serially connected truncated spherical sections, the ends of which converge. Ball bearings between the sections permit relative rotation. The proximal end of the first section is connected to the torso covering by a ball bearing and the distal end of the outermost section is connected to the elbow or thigh covering by a ball bearing. The sections are equi-angular and this alleviates lockup, the condition where the distal end of the joint leaves the plane in which the user is attempting to flex. The axes of rotation of the bearings and the bearing mid planes are arranged to intersect in a particular manner that provides the joint with a minimum envelope. In one embodiment, the races of the bearing between the innermost section and the second section is partially within the inner race of the bearing between the torso and the innermost spherical section further to reduce bulk.
NASA s next generation of space suit systems will place new demands on the pump used to circulate cooling water through the life support system and the crew s liquid cooling garment. Long duration missions and frequent EVA require increased durability and reliability; limited resupply mass requirements demand compatibility with recycled water, and changing system design concepts demand increased tolerance for dissolved and free gas and the ability to operate over a broader range of flow rates and discharge pressure conditions. This paper describes the development of a positive displacement prototype pump to meet these needs. A gerotor based design has been adapted to meet pump performance, gas tolerance, and durability requirements while providing a small, lightweight pump assembly. This design has been detailed and implemented using materials selected to address anticipated water quality and mission needs as a prototype unit for testing in NASA laboratories. Design requirements, pump technology selection and design, performance testing and test results will be discussed.
NASA's next generation of space suit systems will place new demands on the pump used to circulate cooling water through the life support system and the crew's liquid cooling garment. Long duration missions and frequent EVA require increased durability and reliability; limited resupply mass requirements demand compatibility with recycled water, and changing system design concepts demand increased tolerance for dissolved and free gas and the ability to operate over a broader range of flow rates and discharge pressure conditions. This paper describes the development of a positive displacement prototype pump to meet these needs. A gerotor based design has been adapted to meet pump performance, gas tolerance, and durability requirements while providing a small, lightweight pump assembly. This design has been detailed and implemented using materials selected to address anticipated water quality and mission needs as a prototype unit for testing in NASA laboratories. Design requirements, pump technology selection and design, performance testing and test results will be discussed.
This joint mobility KC lecture included information from two papers, "A Method for and Issues Associated with the Determination of Space Suit Joint Requirements" and "Results and Analysis from Space Suit Joint Torque Testing," as presented for the International Conference on Environmental Systems in 2009 and 2010, respectively. The first paper discusses historical joint torque testing methodologies and approaches that were tested in 2008 and 2009. The second paper discusses the testing that was completed in 2009 and 2010.
Spacesuits are complex engineering systems that sustain human health and enable performance outside Earth-like environments. These systems must support human mobility and physical workload demands while minimizing injury risk during extravehicular activity (EVA). Future EVA operations on the Lunar surface are expected to be more frequent and require higher physical workloads than previously during the ISS, Shuttle, and Apollo programs. To characterize the workloads and ergonomics needs a suit must support, the kinematics of the space suit must be measured during operationally-relevant tasks in ground analog environments. Kinematics capture of the suit is challenging for traditional optical motion capture (OMC) approaches due to marker occlusion, harsh lighting or environmental conditions, and tests with suit surrogates in outdoor field environments. To this end, engineers at NASA are developing the Augmented Suit Inverse Kinematics (ASIK) system, a complete motion capture method and inverse kinematics solver which relies solely on a network of wireless inertial measurement units (IMUs) attached to the major kinematic segments of the spacesuit. The ASIK modeling language allows for the simple inclusion of probabilistic priors such as suit size and shape or IMU poses. The ASIK system was tested in a 7-subject pilot study. Each subject donned NASA’s new prototype exploration spacesuit in the Active Response Gravity Offload System (ARGOS) facility at Johnson Space Center in Houston, TX. The suits were outfitted with 12 IMUs to estimate lower body and trunk kinematics. The suits were also outfitted with a set of reflective OMC markers, and traditional OMC data was collected and processed. Characterization of the ASIK-derived suit joint angles’ accuracy against an optical motion capture datum will be presented. Discussion of these results, as well as discussion of system calibration and nuances of mathematical observability, will be included.
A technique for recovering data for the range of motion of a subject wearing a space suit is described along with the validation of this technique on an EVA space suit. Digitized data are automatically acquired from video images of the subject; three-dimensional trajectories are recovered from these data, and can be displayed using three-dimensional computer graphics. Target locations are recovered using a unique video processor and close-range photogrammetry. It is concluded that such data can be used in such applications as the animation of anthropometric computer models.
Engineering study and analysis of water vapor mass transfer in space suit
An effort is underway to determine the coating material of choice for the AX-5 prototype hard space suit. Samples of 6061 aluminum have been coated with one of 10 selected metal coatings, and subjected to corrosion, abrasion, and thermal testing. Changes in reflectance after exposure are documented. Plated gold exhibited minimal degradation of optical properties. A computer model is used in evaluating coating thermal performance in the EVA environment. The model is verified with an experiment designed to measure the heat transfer characteristics of coated space suit parts in a thermal vacuum chamber. Details of this experiment are presented.
Solar reflectance as function of incidence angle and total hemispherical emittance of space suit materials
The Trace Contaminant Control System (TCCS), located within the ventilation loop of the Portable Life Support System (PLSS) of the Constellation Space Suit Element (CSSE), is responsible for removing hazardous trace contaminants from the space suit ventilation flow. This paper summarizes the results of a trade study that evaluated if trace contaminant control could be accomplished without a TCCS, relying on suit leakage, ullage loss from the carbon dioxide and humidity control system, and other factors. Trace contaminant generation rates were revisited to verify that values reflect the latest designs for CSSE pressure garment materials and PLSS hardware. Additionally, TCCS sizing calculations were performed and a literature survey was conducted to review the latest developments in trace contaminant technologies.
Water vapor condensation and adsorption techniques for passive humidity control in space suits
Presented is an overview of the development of the integral thermal/micrometeoroid garment (ITMG) used for protection of a space-suited crewmember from hazards of various extravehicular environments. These hazard conditions can range from thermal extremes, meteoroid and debris particles, and radiation conditions in near-earth orbits and free space to sand and dust environments encountered on lunar or planetary surfaces. Representative ITMG materials cross-section layups are identified and described for various space-suit configurations ranging from the Gemini Program to planned protective requirements and considerations for anticipated Space Station EV operations.
Presented is an overview of the development of the integral thermal/micrometeoroid garment (ITMG) used for protection of a space-suited crewmember from hazards of various extravehicular environments. These hazard conditions can range from thermal extremes, meteoroid and debris particles, and radiation conditions in near-earth orbits and free space to sand and dust environments encountered on lunar and planetary surfaces. Representative ITMG materials cross-section layups are identified and described for various space suit configurations ranging from the Gemini program to planned protective requirements and considerations for anticipated Space Station EV operations.
This paper discusses the current focus of NASA's Advanced Space Suit Pressure Garment Technology Development team's efforts, the status of that work, and a summary of longer term technology development priorities and activities. The Exploration Extra-vehicular Activity Unit (xEMU) project's International Space Station Demonstration Suit (xEMU Demo) project continues to be the team's primary customer and effort. In 2018 the team was engaged in addressing hardware design changes identified in the Z-2 pressure garment prototype Neutral Buoyancy Laboratory (NBL) test results. These changes will be discussed. Additionally components whose first iterations were produced in 2018 will be discussed. A full pressure garment prototype, termed Z-2.5, was assembled that is composed of updated and first prototype iteration hardware. Z-2.5 NBL testing, performed from October 2018 through April 2019 will inform final design iterations in preparation for the xEMU Demo preliminary design review planned to occur in the third quarter of government fiscal year 2019. A primary objective of the Z-2.5 NBL testing is to validate changes made to the hard upper torso geometry, which depart from the planetary walking suit upper torso geometry that has been used over the last 30 years. The team continues to work technology development, with GFY2018 work being used to supplement and feed the gaps left by the scope defined for the xEMU Demo. Specifically, a Phase IIx Small Business Innovative Research Grant to mature durable bearings that are compatible with a dust environment and a grant funded by the Science Technology Mission Directorate, Lightweight and Robust Exploration Space Suit (LARESS) project, to mature planetary impact requirements and hardware will be described. Finally, a brief review of longer-term pressure garment challenges and technology gaps will be presented to provide an understanding of the advanced pressure garment team's technology investment priorities and needs.
Any non-robotic mission to the Mars surface will need to rely on various life support technologies. The large metabolic generation rate and low tolerance to elevated levels of carbon dioxide (CO2) in the Mars atmosphere make CO2 removal one of the preeminent tasks in this domain. In addition, these same features provide a strong impetus for using regenerable CO2 removal technologies. In the past, many of these regenerable technologies have relied on the low partial pressure CO2 surrounding the vehicle to provide an ultimate sink for removing this gas contaminant, however any Mars mission will have to overcome the presence of the Mars atmosphere. This paper describes the investigation of methods to capture the exhaled CO2 from a suited crewmember before it becomes diluted with the high volumetric air flow present within the space suit. Typical expired air contains CO2 partial pressures in the range of 20-35 mm Hg. This research investigated methods to capture this high partial pressure CO2 prior to its dilution with the low partial pressure CO2 ventilation flow. Specifically the research looked at potential designs for a collection cup for use inside the space suit helmet. This collection cup should not be considered the same as a breathing mask typical of that worn by firefighters, etc. Instead, the collection cup is a non-contact device that makes use of detailed analyses of the ventilation flow environment within the helmet. The research used a detailed Computational Fluid Dynamic (CFD) code called Fluent to provide modeling of the various gas species (CO2, water vapor, O2) as they pass through a helmet. This same model was used to numerically evaluate several different collection cup designs for this same CO2 segregation effort.
The elements of the test program for the space suit to be used on Space Station Freedom are noted in viewgraph form. Information is given on evaluation objectives, zero gravity evaluation, mobility evaluation, extravehicular activity task evaluation, and shoulder joint evaluation.
Automatically controlled heat removal in water cooled space suits