A new system has been designed to simulate orbital-extravehicular (EVA) work to provide for real-time measurement of physiological parameters. Such a system described here incorporates an experimental protocol, exercising subject, controlled-atmosphere chamber, EVA-work simulation exercise device, medical instrumentation and a data acquisition system. Applications of the neutral-buoyancy method and other laboratory-simulation methods are described. This information is presented to facilitate the understanding of this exercise device as a possible additional orbital-EVA work-simulation tool.Important engineering issues associated with the design of the proposed system are discussed. They are: biomechanical influences on the exercise device design, chamber volume and instrument sensitivity in relation to measurement system response time, exercise device counterbalancing with respect to the extravehicular mobility unit (EMU) mass inertia, and incorporation of suit joint-flexure energy cost. This simulation system may be ideal for preflight astronaut conditioning as well as physiological studies such as nutritional assessments, thermoregulation experiments, work efficiency investigations, fatigue and endurance research, etc.