Modeling Occupational Fingernail Onycholysis Disorders in the Population of US Astronauts Who Have Engaged in Extravehicular Activity.

Objectives: Spacesuits are designed to be reliable personal spacecraft that preserve the life and well-being of the astronaut from the extremes of space. However, materials, operating pressures, and suit design requirements often result in a risk of musculoskeletal discomfort and injury to various areas of the body. In particular, this investigation looked at fingernails and their risk of developing onycholysis.

The Partial Pressure of Inspired Carbon Dioxide Exposure Levels in the Extravehicular Mobility Unit.

NASA has been making efforts to assess the carbon dioxide (CO₂) washout capability of spacesuits using a standard CO₂ sampling protocol. This study established the methodology for determining the partial pressure of inspired CO₂ (Pco₂) in a pressurized spacesuit. We applied the methodology to characterize Pco₂ for the extravehicular mobility unit (EMU).

Carbon Monoxide Levels in the Extravehicular Mobility Unit by Modeling and Operational Testing.

Carbon monoxide (CO) is a toxic gas with potential for detriment to spaceflight operations. An analytical model was developed to investigate if a maximum CO contamination of 1 ppm in the oxygen (O₂) supply reached dangerous levels during extravehicular activity (EVA). Occupational monitoring pre- and postsuited exposures provided supplementary data for review.

Retrospective Evaluation of Clinical Symptoms Due to Mild Hypobaric Hypoxia Exposure in Microgravity.

Introduction: A habitat atmosphere of 34% oxygen (O2) and 66% nitrogen (N2) at 8.2 psia (56.5 kPa) is proposed to minimize the risk of decompression sickness during extravehicular activity.

Hemoglobin Oxygen Saturation with Mild Hypoxia and Microgravity.

Introduction: Microgravity (μG) exposure and even early recovery from μG in combination with mild hypoxia may increase the alveolar-arterial oxygen (O2) partial pressure gradient.

Methods: Four male astronauts on STS-69 (1995) and four on STS-72 (1996) were exposed on Earth to an acute sequential hypoxic challenge by breathing for 4 min 18.0%, 14.

Hypobaric Decompression Sickness Treatment Model.

Introduction: The Hypobaric Decompression Sickness (DCS) Treatment Model links a decrease in computed bubble volume from increased pressure (ΔP), increased oxygen (O2) partial pressure, and passage of time during treatment to the probability of symptom resolution [P(SR)]. The decrease in offending volume is realized in two stages: 1) during compression via Boyles law; and 2) during subsequent dissolution of the gas phase via the oxygen window.

Methods: We established an empirical model for the P(SR) while accounting for multiple symptoms within subjects.

The preferred walk to run transition speed in actual lunar gravity.

Quantifying the preferred transition speed (PTS) from walking to running has provided insight into the underlying mechanics of locomotion. The dynamic similarity hypothesis suggests that the PTS should occur at the same Froude number across gravitational environments. In normal Earth gravity, the PTS occurs at a Froude number of 0.