The Design of Instrumentation and Analytical Software to Characterize Lower Leg Temperature as a Function of Simulated Partial Gravity in Order to Optimize Future Spacesuit Design
Abstract
For nearly 60 years, astronauts have ventured outside of their spacecraft into the extreme environment of space, performing extravehicular activities (EVAs). The astronauts are protected from the harsh environment of space, including hard vacuum, micrometeroids, and large temperature variations, by an EVA suit. A critical component of the EVA suit system is the undergarment which is used to regulate body temperature by rejecting excess heat to vacuum, called the liquid cooling and ventilation garment (LCVG). The current LCVG design used on the Space Shuttle and for the International Space Station (ISS) has not changed in more than 40 years. It was designed with the assumption that the mechanisms and body locations in which heat is rejected in the microgravity environment of Low Earth Orbit (LEO) (1x10^-6 g) is equivalent to that in 1g (9.81 m/s^2) on the surface of the Earth. However, this has never been verified in LEO. Dr. Bonnie J. Dunbar, Director of the Aerospace Human Systems Laboratory (AHSL), is challenging that hypothesis based on known changes in body morphology and redistribution of body fluids responsible for heat rejection, in LEO. If the location of body heat rejection does change in LEO, changes in the design of the LCVG could lead to reduced EVA suit mass and consumables (such as circulating coolant water). Prior on orbit data indicates that the lower body (e.g. leg) is the most logical focus for the research. The purpose of this thesis research is to design and test an instrument suite which would be used for a formal study of her hypothesis using human subjects in 1g (9.81 m/s^2), but taking advantage of previously demonstrated micro- and hypo-gravity earth-based analogs. The results of this thesis include trade studies of IR cameras and a 3D surface scanner, the selection of the tilt table as the microgravity and hypo-gravity analog, design of the integrated system, results from a proof of concept experiment, preliminary results for registration of the IR camera images, proposed experimental procedures and recommendations for future design optimization.
Subject
spaceflightEVA suit
EVA
human thermal control
human IR imaging
LCVG
liquid cooling and ventilation garment
human systems integration
Citation
Heinimann, Alexandra (2020). The Design of Instrumentation and Analytical Software to Characterize Lower Leg Temperature as a Function of Simulated Partial Gravity in Order to Optimize Future Spacesuit Design. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /191674.