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Creating a Lunar EVA Work Envelope
Technical Paper
2009-01-2569
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
A work envelope has been defined for weightless Extravehicular Activity (EVA) based on the Space Shuttle Extravehicular Mobility Unit (EMU), but there is no equivalent for planetary operations. The weightless work envelope is essential for planning all EVA tasks because it determines the location of removable parts, making sure they are within reach and visibility of the suited crew member. In addition, using the envelope positions the structural hard points for foot restraints that allow placing both hands on the job and provides a load path for reacting forces.
EVA operations are always constrained by time. Tasks are carefully planned to ensure the crew has enough breathing oxygen, cooling water, and battery power. Planning first involves computers using a virtual work envelope to model tasks, next suited crew members in a simulated environment refine the tasks. For weightless operations, this process is well developed, but planetary EVA is different and no work envelope has been defined.
The primary difference between weightless and planetary work envelopes is gravity. It influences anthropometry, horizontal and vertical mobility, and reaction load paths and introduces effort into doing “overhead” work. Additionally, the use of spacesuits other than the EMU, and their impacts on range of motion, must be taken into account. This paper presents the analysis leading to a concept for a planetary EVA work envelope with emphasis on lunar operations. There is some urgency in creating this concept because NASA has begun building and testing development hardware for the lunar surface, including rovers, habitats and cargo off-loading equipment. Just as with microgravity operations, a lunar EVA work envelope is needed to guide designers in the formative stages of the program with the objective of avoiding difficult and costly rework.
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Griffin, B., Howard, R., Rajulu, S., and Smitherman, D., "Creating a Lunar EVA Work Envelope," SAE Technical Paper 2009-01-2569, 2009, https://doi.org/10.4271/2009-01-2569.Also In
References
- “Space Shuttle System Payload Accommodations,” NSTS 07700. Volume XIV, Revision K, Appendix 7: Extra Vehicular Activities 2000
- “The Influence of Zero-g and Acceleration on the Human Factors of Spacecraft Design,” Griffin B. NASA Design Guide, JSC 14581 1978
- “Concept of Space Suit Enclosure for Planetary Exploration,” Abramov I. Moiseyev N. Stoklitsky A. SAE 2001-01-2168
- U.S Spacesuits Thomas K. S. McMann H. J. Springer-Praxis 2006 10: 0-387-27919-9
- Occupational Safety Health Administration (OSHA), Fixed Ladders. - 1917.118, Protection Against Falls
- “I-Suit Advanced Spacesuit Design Improvements and Performance Testing,” Graziosi D. Lee Ryan SAE 2003-01-2443