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In prior studies of the current Shuttle Spacesuit (SSA), where basic fabric lay-ups were tested for shielding capabilities, it was found that the fabric portions of the suit give far less protection than previously estimated due to porosity and non-uniformity of fabric and LCVG components. In addition, overall material transmission properties were less than optimum. A number of alternate approaches are being tested to provide more uniform coverage and to use more efficient materials. We will discuss in this paper, recent testing of new material lay-ups/configurations for possible use in future spacesuit designs.

A detailed spacesuit computational model is being developed at the Langley Research Center for radiation exposure evaluation studies. The details of the construction of the spacesuit are critical to estimation of exposures and assessing the risk to the astronaut on EVA. Past evaluations of spacesuit shielding properties assumed the basic fabric lay-up (Thermal Micrometeroid Garment, fabric restraints, and pressure envelope) and Liquid Cooling and Ventilation Garment (LCVG) could be homogenized as a single layer overestimating the protective properties over 60 percent of the fabric area. The present spacesuit model represents the inhomogeneous distributions of LCVG materials (mainly the water filled cooling tubes). An experimental test is performed using a 34-MeV proton beam and high-resolution detectors to compare with model-predicted transmission factors. Some suggestions are made on possible improved construction methods to improve the spacesuit’s protection properties.

Based on recently revised space debris environment estimations for Low Earth Orbit (LEO) altitudes, the level of Micrometeoroid/Debris (M/D) protection afforded by the current Shuttle space suit layup may not be sufficient for application to the Space Station Freedom Program. Enhanced M/D protection could be incorporated through the use of a flexible multi-hull Thermal Micrometeoroid Garment (TMG) based on advanced fabric material layups. A lightweight, flexible TMG design for enhanced space suit M/D protection would potentially consist of an outer layer or “shield” comprised of Orthofabric, multi-layers of aluminized Mylar and a layer of silicone rubber loaded with micron sized particles of tungsten. The second layer or “backup sheet” would be comprised of a layer(s) of a fabric material such as Spectra (UHMWPE). The shield layers would fragment and/or vaporize the M/D projectile while the backup sheet would stop the resultant debris cloud.