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Honeywell Engines and Systems (E&S) Environmental Control Systems (ECS) division has been developing a 50 kW proton exchange membrane (PEM) fuel cell brassboard system for automotive application as part of a U.S. Department of Energy (DOE) program. A primary issue in the development of the brassboard is the automatic control of the system. A preferred DOE requirement is dynamic load following from idle to peak power. Since the PEM stacks require precise inlet condition control for both the air and fuel to achieve high efficiency, the control system must provide good dynamic tracking and low steady-state error over the entire operating range. In addition, the controller must provide automatic system start-up and shutdown, built-in-test (BIT) to monitor key system parameters, and take corrective action if those parameters reach an unsafe condition. The purpose of this paper is to present the control system design approach taken by the authors to achieve those goals.

The existing Shuttle Extravehicular Mobility Unit (EMU) has served NASA well for sometime, however, it uses a large amount of consumables including water, O2 and lithium hydroxide. In order for extended missions to the Moon and Mars to be successful, two new portable life support systems (PLSS) designs have been proposed that will minimize the amount of consumables used and will be more reliable due to simplified designs. This paper considers one such PLSS, currently designated the Cryogenic-PLSS (CPLSS). The reason for this designation is because it uses liquid O2 to provide the breathing gas for the astronaut and to provide backup cooling for the astronaut. In order to understand how the system will function in space and to evaluate final design parameters, a transient thermal model has been developed using the software package MATLAB/Simulink.

The NASA JSC Shuttle EMU computer model (SINDA EMU) is presently used to analyze the thermal behavior of the Space Shuttle EMU. This paper uses the SINDA EMU model along with EMU experimental and flight data to investigate and define several performance characteristics of the Space Shuttle EMU related to thermal comfort control.

This paper discusses the development of an exercise chamber as one of the requirements for a planned generalized EVA Simulation Test Bed. The design of the outer chamber and associated environmental control equipment is discussed, followed by a sensitivity analysis of the parameters of a human thermal model leading to a design for the inner chamber.