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Sanders, Robert W.

Publications and source records attributed to Sanders, Robert W..

3 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

The "Space Activity Suit" - A Historical Perspective and A Primer on the Physiology of Mechanical Counter-Pressure

Since the 1950s, mechanical counter-pressure (MCP) has been investigated as a possible alternative design concept to traditional extra-vehicular activity (EVA) space suits. While traditional gas-pressurized EVA suits provide physiological protection against the ambient vacuum by means of pressurized oxygen to at least 3.1 pounds per square inch absolute (160 millimeters of mercury), MCP provides protection by direct application of pressure on the skin by a fabric. In reviewing the concept, MCP offers distinct potential advantages to traditional EVA suits: lower mass, reduced consumables, increased mobility, increased comfort, less complexity, and improved failure modes. In the mid 1960s to early 1970s, Dr. Paul Webb of Webb Associates developed and tested such a suit under funding from NASA Langley Research Center. This "Space Activity Suit" (SAS) was improved many times while testing in the laboratory and an altitude chamber to as low as 0.3 pounds per square inch absolute (15 millimeters of mercury). This testing, and the reports by Webb documenting it, are often presented as evidence of the feasibility of MCP. In addition, the SAS reports contain a wealth of information regarding the physiological requirements to make MCP work at the time, which is still accurate today. This paper serves to document the Space Activity Suit effort and analyze it in today's context.

McFarland, Shane M.↗
NASA NTRS2019

Suited Ground Vacuum Chamber Testing Decompression Sickness Tiger Team Report

Suited vacuum chamber testing is critical to flight crew training, sustaining engineering, and development engineering. Most suited vacuum chamber testing at NASA’s Johnson Space Center (JSC) involves crewmembers or human test subjects working at a hypobaric pressure of 4.3 psia, which requires that an oxygen prebreathe be performed prior to decompression to reduce the risk of decompression sickness (DCS). Since 1986, NASA’s policy has been to require a 4-hour resting prebreathe for hypobaric chamber exposures of 4.2 psia lasting greater than 30 minutes. There have been no reports of Type II (i.e., serious, potentially life-threatening) DCS at NASA while using this prebreathe protocol. Several chamber runs, believed to be approximately 5% of all runs, are believed to have been terminated due to Type I DCS symptoms that were performance impairing; however, detailed records of DCS symptoms during suited vacuum chamber runs are not available. The adequacy of the 4-hour prebreathe protocol, as well as the processes by which prebreathe protocols and policies are established, became the subject of significant discussion in April 2018 when medical planning was initiated for chamber runs that were scheduled to occur later in 2018 that would last 8 hours or more with high metabolic rates.

Abercromby, Andrew F. J.↗