The four components portland cement‐dicalcium silicate, C2S (Ca2SiO4); tricalcium silicate, C3S (Ca3SiO5); tricalcium aluminate, C3A (Ca3Al2O6); and tetracalcium aluminate iron oxide, C4AF (Ca4Al2Fe3O10)‐were formed using a solution‐polymerization route based on poly(vinyl alcohol) (PVA) as the polymer carrier. The powders were characterized using X‐ray diffraction techniques, BET specific surface area measurements, and scanning electron microscopy. This method produced relatively pure, synthetic cement components of submicrometer or nanometer crystallite dimensions, high specific surface areas, as well as extremely high reactivity at relatively low calcining temperatures. The PVA content and its degree of polymerization had a significant influence on the homogeneity of the final powders. Two types of degree of polymerization (DP) PVA were used. Lower crystallization temperatures and smaller particle size powders were obtained from the low‐DP‐type PVA at optimum content.

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The objective of this project was to develop a comprehensive methodology to assess the suit fit and performance differences between a nominally sized extravehicular mobility unit (EMU) spacesuit and a nominal +1 (plus) sized EMU. Method: This study considered a multitude of evaluation metrics including 3D clearances and pressure point mapping to quantify potential issues associated with using offnominal suit sizes. Results: There were minimal differences with using a plus suit size. Discussion: Analysis of the results indicates that future suit size evaluations should consider this ergonomic approach to understand and mitigate potential suit fit and performance issues.

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The 'fit' of a garment is often considered a subjective measure of garment quality. However, some experts attest that a complaint of poor garment fit is a symptom of inadequate or excessive ease, the space between the garment and the wearer. Fit has traditionally been hard to quantify, and space suits are an extreme example, where fit is difficult to measure but crucial for safety and operability. A proper space suit fit is particularly challenging because of NASA's need to fit an incredibly diverse population (males and females from the 1 st to 99 th percentile) while developing a minimum number of space suit sizes.Because so few sizes are available, the available space suits must be optimized so that each fits a large segment of the population without compromising the fit of any one wearer. Therefore, current simplistic sizing systems will not be adequate.Traditional sizing schemes attempt to subdivide people by paired dimensions like height and weight. However, a sizing system based on predicting minor dimensions from these so-called key dimensions does not reflect the variability of human shapes, even among people of the same height and weight. The problem becomes even more complex when attempting to fit both men and women with the same sizing scheme. Instead, more advanced multivariate methods should be used to group wearers into optimized categories that can translate into suit sizing parameters. A so-called integrated approach to sizing can ensure that a compromise is reached between sizing for men and women, so that neither group is excluded. The sizing scheme can then be combined with range of motion testing and subjective feedback, to evaluate and fine tune the sizes and to add or subtract ease from areas of the suit.Successfully predicting wearer dimensions and providing the appropriate amount of ease and adjustability is crucial in developing space suits, where a poor fit can decrease mobility and lead to wearer discomfort or even injury. Suit designers will need to know the sizes of the people they will need to fit, the amount of adjustability the suits will need, and how well a suit must fit to be usable. Additionally, it will be important to make sure a suit fits before it is evaluated, or used to evaluate other systems. Therefore, the Anthropometry and Biomechanics Facility at NASA's Johnson Space Center is working to combine traditional and more advanced methods of quantifying fit, to aid the designers of the next generation of space suits. This paper describes the issues that are faced in attempting to fit suits to a diverse population, and some of the methods that can be used to surmount these difficulties and provide the best possible compromise between fit and accommodation.

The gloved hand is one of an astronaut's primary means of interacting with the environment, and any restrictions imposed by the glove can strongly affect performance during extravehicular activity (EVA). Glove restrictions have been the subject of study for decades, yet previous studies have generally been unsuccessful in quantifying glove mobility and tactility. Past studies have tended to focus on the dexterity, strength, and functional performance of the gloved hand; this provides only a circumspect analysis of the impact of each type of restriction on the glove's overall capability. The aim of this study was to develop novel capabilities to provide metrics for mobility and tactility that can be used to assess the performance of a glove in a way that could enable designers and engineers to improve their current designs. A series of evaluations were performed to compare unpressurized and pressurized (4.3 psi) gloved conditions with the ungloved condition. A second series of evaluations were performed with the Thermal Micrometeoroid Garment (TMG) removed. This series of tests provided interesting insight into how much of an effect the TMG has on gloved mobility -in some cases, the presence of the TMG restricted glove mobility as much as pressurization did. Previous hypotheses had assumed that the TMG would have a much lower impact on mobility, but these results suggest that an improvement in the design of the TMG could have a significant impact on glove performance. Tactility testing illustrated the effect of glove pressurization, provided insight into the design of hardware that interfaces with the glove, and highlighted areas of concern. The metrics developed in this study served to benchmark the Phase VI EVA glove and to develop requirements for the next-generation glove for the Constellation program.

Suboptimal suit fit is a known risk factor for crewmember shoulder injury. Suit fit assessment is however prohibitively time consuming and cannot be generalized across wide variations of body shapes and poses. In this work, we have developed a new design tool based on the statistical analysis of body-shape scans. This tool is aimed at predicting the skin deformation and shape variations for any body size and shoulder pose for a target population. This new process, when incorporated with CAD software, will enable virtual suit fit assessments, predictively quantifying the contact volume, and clearance between the suit and body surface at reduced time and cost.

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