The suitport concept has been recently implemented as part of the small pressurized lunar rover (Currently the Space Exploration vehicle, or SEV) and the Multi-Mission Space Exploration Vehicle (MMSEV) concept demonstrator vehicle. Suitport replaces or augments the traditional airlock function of a spacecraft by providing a bulkhead opening, capture mechanism, and sealing system to allow ingress and egress of a spacesuit while the spacesuit remains outside of the pressurized volume of the spacecraft. This presents significant new opportunities to EVA exploration in both microgravity and surface environments. The suitport concept will enable three main improvements in EVA by providing reductions in: pre-EVA time from hours to less than thirty minutes; airlock consumables; contamination returned to the cabin with the EVA crewmember. To date, the first generation suitport has been tested with mockup suits on the rover cabins and pressurized on a bench top engineering unit. The work on the rover cabin has helped define the operational concepts and timelines, and has demonstrated the potential of suitport to save significant amounts of crew time before and after EVAs. The work with the engineering unit has successfully demonstrated the pressurizable seal concept including the ability to seal after the introduction and removal of contamination to the sealing surfaces. Using this experience, a second generation suitport was designed. This second generation suitport has been tested with a spacesuit prototype using the pressure differentials of the spacecraft. This test will be performed using the JSC B32 Chamber B, a human rated vacuum chamber. This test will include human rated suitports, the suitport compatible prototype suit, and chamber modifications. This test will bring these three elements together in the first ever pressurized donning of a rear entry suit through a suitport. This paper presents design of a human rated second generation suitport, modifications to the JSC human rated chamber B to accept a suitport, and a compatible space suit to support pressurized human donning of the pressurized suit through a suitport. Design challenges and solutions and compromises required to develop the system are presented. Initial human testing results are presented.
Requirements for using a space suit during ground testing include providing adequate carbon dioxide (CO 2 ) washout for the suited subject. Acute CO 2 exposure can lead to symptoms including headache, dyspnea, lethargy and eventually unconsciousness or even death. Symptoms depend on several factors including partial pressure of CO 2 (ppCO 2 ), duration of exposure, metabolic rate of the subject and physiological differences between subjects. The objective of this test was to characterize inspired oronasal ppCO 2 in the Rear Entry I-Suit (REI) and the Enhanced Mobility Advanced Crew Escape Suit (EM-ACES) across a range of workloads and flow rates for which ground testing is nominally performed.Three subjects were tested in each suit. In all but one case, each subject performed the test twice to allow for comparison between tests. Suit pressure was maintained at 4.3 psid. Subjects wore the suit while resting, performing arm ergometry, and walking on a treadmill to generate metabolic workloads of approximately 500 to 3000 BTU/hr. Supply airflow was varied at 6, 5 and 4 actual cubic feet per minute (ACFM) at each workload. Subjects wore an oronasal mask with an open port in front of the mouth and were allowed to breathe freely. Oronasal ppCO 2 was monitored real-time via gas analyzers with sampling tubes connected to the oronasal mask. Metabolic rate was calculated from the total CO 2 production measured by an additional gas analyzer at the air outlet from the suit. Real-time metabolic rate was used to adjust the arm ergometer or treadmill workload to meet target metabolic rates.In both suits, inspired CO 2 was primarily affected by the metabolic rate of the subject, with increased metabolic rate resulting in increased inspired ppCO 2 . Suit flow rate also affected inspired ppCO 2 , with decreased flow causing small increases in inspired ppCO 2 . The effect of flow was more evident at metabolic rates ≥ 2000 BTU/hr. Results were consistent between suits, with the EM-ACES demonstrating slightly better CO 2 washout than the REI suit, but not statistically significant. Regression equations were developed for each suit to predict the mean inspired ppCO 2 as a function of metabolic rate and suit flow rate.This paper provides detailed descriptions of the test hardware, methodology and results, as well as implications for future ground testing in the REI and EM-ACES.https://ntrs.nasa.gov/search.jsp?R=20110020555 2018-05-10T23:29:44+00:00Z
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