Approaches to decompression safety support of EVA for orbital and interplanetary missions
- Paper number
IAC-08.A1.3.11
- Author
Dr. Vladimir P. Katuntsev, Institute for Biomedical Problems, Russia
- Year
2008
- Abstract
The paper is devoted to the analysis of possible methods for decompression safety support of extravehicular activity (EVA) in order to ground the perspective approaches for solution of decompression sickness (DCS) problem in space missions of the near and distant future. The current Russian and U.S. spacecrafts as well as the International Space Station (ISS) have the normobaric gas atmospheres. The level of operating pressure in space suits used onboard ISS corresponds to 40 kPa for Russian space suit “Orlan” and 30 kPa for US space suit “EMU”. To protect EVA crewmembers from DCS the procedure of partial denitrogenation is used prior depressurization of airlock and beginning of EVA. The duration of preliminary denitrogenation is 30 min for EVA in space suit “Orlan” and 2 h 20 min - 4 h (in some cases, even longer) for EVA in space suit “EMU”. To date there has been no incidence of DCS during orbital EVAs. However, at 30-40 kPa in space suits crewmembers often experience general and arm fatigue during and after long EVA. Such high value of surplus pressure into the current space suit increases significantly its rigidness that limits movement activity of crewmembers during EVA and, thus, reduces DCS risk. Perspective space programs goals include permanent occupation of the ISS and missions to the Moon and Mars. Due to gravitational forces that exist on the Moon and Mars, the current space suits will be also too heavy for planetary EVA. The main biomedical requirements to a planetary space suit have to include, among others, low mass of EVA system, high mobility and dexterity of space suit enclosure with optimal design of joints, especially, for locomotion and reliable protection against DCS with a very short or zero preoxygenation period. Reviewed here are the possibilities for the use of preoxygenation, hypobaric gas atmosphere in space cabin, idea of substitution of nitrogen in normobaric gas atmosphere of space cabin to another inert gas (helium and neon) as countermeasures against DCS in EVA crewmembers. Physiological aspects of the conception for space suit with high operating pressure are considered.
- Abstract document
- Manuscript document
IAC-08.A1.3.11.pdf (🔒 authorized access only).
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