A Methodology for Developing an Intravehicular Activity Spacesuit Sizing Scheme

Intravehicular activity (IVA) spacesuits are essential for protecting astronauts on crewed missions during launch, abort, and entry. Proper sizing is crucial for optimal performance, and historically, both set-sizing schemes and custom sizing have been used to fit IVA spacesuits to astronauts. While custom spacesuits provide optimal fit, a fixed spacesuit sizing scheme is better optimized for spacecraft with higher flight rates, allowing for the reuse of the spacesuit. Provided the sizing scheme is appropriate for the mission and the anthropometric range and each spacesuit has sufficient resizability inherent to the design, a fixed sizing scheme is better tailored for certain applications. With an increase in the number of companies engaging in space travel and the frequency of their missions, David Clark Company Incorporated further refined a unique process for developing an IVA spacesuit sizing scheme. This paper presents the methodology for designing a spacesuit sizing system based on best practices. The development of an IVA spacesuit sizing scheme begins by assessing the requirements and concepts of operations for the spacesuit and identifying the critical measurements that form the basis of the sizing system. The next step is to determine the adjustability and allowable excess in the critical measurement areas to ensure sufficient mission performance. Then, an initial sizing scheme is created based on sizing data of military personnel and validated against available astronaut sizing data to ensure it appropriately fits the target population. Next, the initial identification of spacesuit sizes for astronauts is demonstrated through the use of development units and fit checks, which are essential due to the subjective nature of comfort. Finally, lessons learned on IVA spacesuit sizing scheme design are discussed. The methodology presented is a flexible and extensible tool that can be applied to existing and emerging spaceflight companies.