the near term, and recent lunar base studies have been completed [International Lunar Initiative, 1988], this examination is secondary in scope to the on-orbit operations which will be required to a greater or lesser extent, regardless of lunar resource use. Crew Health and Safety Concerns The same basic concerns apply to lunar manufacturing as have been outlined for on-orbit construction. However, readaptation to a 0.16 G environment after an approximately three day flight to the Moon must be examined. The known physiological effects of space flight have been achieved chiefly though exposure to a micro gravity environment. Many physiological responses (cardiovascular, musculo-skeletal, and especially vestibular) will be substantially different in a 0.16 G environment. Exercise regimes for cardiovascular and musculo-skeletal maintenance may be modified. Vestibular readaptation may reintroduce or heighten space motion sickness symptoms. Radiation is a substantial medical problem for lunar activities as the Moon has no radiation-absorbing atmosphere and no overall magnetic field to deflect incoming charged particles. The Earth has a mean radiation dose equivalent of 0.1 - 0.2 rem / year while the lunar surface radiation dose equivalent is 20 - 50 rem / year [ILI, 1988]. It is proposed that for extended lunar activities the acceptable dose equivalent should be set to 5 rem/year [Lunar Storm Shelter Concept Design, 1988]. Exposures must be monitored with personal dosimeters to keep accurate individual records. For prolonged habitat on the Moon, a shelter with shielding of density 400 g/cm2 is required to bring radiation exposure levels to below 5 rem/year [LSSC, 1988]. In order to be well protected against solar flare activity, shielding should be between 700 - 750 g/cm2. They recommend that without substantial shielding, the duration of lunar stay should not exceed 70 days. These exposures must be considered when planning habitat facilities and duration of astronaut rotation for lunar manufacturing. EVA on the Moon must be accompanied by portable “storm shelter tents” to provide protection from solar flares. Since increased solar activity can be detected between 20 and 30 minutes before it arrives at the lunar surface, these shelters must be placed within 20 minutes travel time of each other and the permanent shelter [LSSCD, 1988]. Creation of a Lunar Atmosphere With construction activities, machinery, and lunar launches, a tenuous lunar atmosphere may be introduced where the residence time of various chemical will depend on their molecular weight. Some of these chemicals might have potentially negative impact on lunar soils and lunar bases. This atmosphere would come chiefly from exhaust fumes and would most likely be toxic to humans as well. Monitoring of toxic substances is essential for human presence and their production should be minimized by utilizing cleaner sources of energy (i.e. solar energy). A potentially greater problem is the dust which may contribute to “atmospheric” problems, especially with substantial disturbance of the lunar surface that mining and manufacturing would provide. This must be examined as well, and dust reduction strategies may be necessary. An expected increase in man - machine interactions with lunar manufacturing increases the risk of occupational injury, including primary medical events such as bone fracture, sprains, crush injuries, other trauma, etc.. Medical Facilities and Crew Habitat The medical and living requirements of a lunar crew would be very similar to those outlined for on- orbit construction. Since the Earth is approximately a three day journey, there needs to be slightly more extensive care available for a manned lunar operation. The main addition would be for capabilities of minor surgery including anesthesia. The medical facilities could be more tailored to an Earth based occupational medicine treatment model. With present technologies, it is recommended that the facilities' life support system be physical/chemical, and partially closed as was the on-orbit design. Extravehicular Activities Man and Machine Coordination Manufacturing and construction in lunar gravity reintroduces the need to overcome weight for material manipulations. This forces a heavy reliance on robotic operations and introduction of man in the loop only when necessary for control or high dexterity operations. Safety controls must be introduced into the robotic operations to insure that maneuvers do not jeopardize the integrity of EVA crew or crew facilities.
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