Search Results

The importance of being able to determine the usage rate of life support subsystem consumables was recognized well before the first Apollo Extravehicular Activity (EVA). Since that time, metabolic activity levels have been evaluated and recorded for each EVA crew member. Throughout the history of the United States space program, EVA metabolic rates have been shown to be variable depending upon the mission scenario and the equipment used. Knowing this historic information is invaluable for current EVA planning activities, as well as for the design of future Extravehicular Mobility Unit (EMU) systems. This paper presents an overview of historic metabolic expenditures for Apollo, Skylab, and Shuttle missions, along with a discussion of the types of EVA crew member activities which lead to various metabolic rate levels, and a discussion on how this data is being used to develop advanced EMU systems.

Developing advanced technology through the prototype phase on a system as complex as a Portable Life Support Subsystem (PLSS) for an Extravehicular Mobility Unit (EMU) is a time and resource consuming process. Experience has shown that most of the decisions controlling the life cycle cost of a system intended for operational use are made very early in the design process. By the preliminary design review most of the design-controlled cost drivers are locked into the design. To ensure a reasonable chance for the design to successfully meet mission requirements, it is best to choose the most promising, most likely-to-succeed technology available in the early stages of breadboard and preprototype development.

The NASA Shuttle Extravehicular Mobility Unit (EMU) uses a non-regenerable absorbent to remove CO2 from an astronaut's breathing loop. A savings in launch weight, storage volume and life cycle cost may be achieved by incorporating a regenerable CO2 removal system into the EMU. This paper will discuss regenerable CO2 sorbents and their impact on the life support system of an EMU. The systems evaluated will be judged on their technical maturity, impact to the EMU, and impacts to space station and shuttle operation