OPERATIONAL FIELD SUPPORT 



During operational phases of the program, an engineering watch was maintained 

 at the command site on a 24-hour basis. Individuals who filled this watch bill 

 were engineers and technicians who had designed, tested, and built the habitat. 

 All were trained to dive on the habitat and had been cross-trained to under- 

 stand both habitat and surface support systems. During the mission, the surface 

 engineer on watch provided technical assistance to the watch director manning 

 the watch director's station. 



HABITAT SYSTEMS PERFORMANCE 



During the mission, the various habitat subsystems were monitored from the 

 surface as well as from the habitat. With the exception of some minor component 

 malfunctions, the habitat performed in a highly successful manner. 



The Environmental Control System (ECS) performance during the mission was excel- 

 lent. Prior to the start of a mission or consecutive series of missions, the 

 oxygen level was adjusted to 11 tp 12% by volume through a nitrogen purge. The 

 aquanauts would then "breathe down" the oxygen over a few days until the partial 

 pressure of oxygen (PO2) was in the operating range (151-165 torr.) where it 

 was maintained relatively constant. The CO2 scrubber had no problem in maintain- 

 ing the partial pressure of carbon dioxide (pC02) below the required 8 millimeter 

 of mercury (mm Hg) , and in most cases the level did not exceed 6 mm Hg. The few 

 instances where the pC02 exceeded this limit were caused by erroneous readings 

 from the carbon dioxide (CO2) analyzer. Baralyme change intervals were longer 

 at night than in the day (due to difference in CO2 production rate) and averaged 

 about 15 hours. Figure 21 indicates fluctuation in p02 and pC02 levels over a 

 typical time period. The data points in Figure 21 are daily averages. In prac- 

 tice, gas monitoring instruments were watched continually and were recorded at 

 2-hour intervals. Daily variations occurred but were maintained within per- 

 missible limits. Figure 22 indicates typical daily variations in pC02 levels. 



The air temperature in the habitat, which was adjustable and selected by the 

 crew, generally ranged from 78° to 83° F. Relative humidity was maintained at 

 45 to 55% which resulted in an extremely comfortable environment. Figure 23 

 shows changes in temperature and relative humidity in each of the habitat com- 

 partments during a typical 28-day period. All other subsystems in the ECS per- 

 formed satisfactorily. 



A number of component failures did occur that required repair and/or adjustment 

 in the ECS. In the inlet air system, both air compressors (one redundant) 

 required replacement of diaphragms and valves. In the CO2 scrubber, the bolt 

 holding the lid on the baralyme canister housing failed twice and required 

 replacement. Both a blower and a pump in the air conditioning system required 

 replacement. It was subsequently determined that the capacitors of these motors 

 burned out due to a large voltage fluctuation in the electrical power system. 

 Late in the program, a leak developed in the external piping for the SCUBA 

 charging system. This portion of the system was isolated by closing shut off 

 valves and the HP air from the surface rerouted through the emergency breathing 

 system to the SCUBA charging panel. Several failures also occurred with the 

 surface high pressure air compressors. 



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