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The US Navy monitors atmospheric constituents aboard nuclear submarines with a ruggedized mass spectrometer called the Central Atmosphere Monitoring System (CAMS). The CAMS aboard each submarine is capable of sensing oxygen, nitrogen, carbon dioxide, carbon monoxide, water vapor and refrigerants in all regularly occupied spaces. This setup fulfills the majority of the Navy’s needs, however, the CAMS is not capable of “sniffing” enclosed spaces nor providing data after certain casualty situations. To meet these two critical needs and provide backup monitoring capability for the CAMS, the US Navy currently uses various gas-sensing colorimetric tubes. Aside from the traditional unpopularity of these tubes with the fleet, recent investigations have shown them to be inefficient, expensive and difficult to obtain. With that background, testing was funded to determine if the colorimetric tubes could be replaced with modern portable atmosphere monitoring equipment.

The atmospheres of US Navy Submarines are unique closed environments in which sailors both live and work for extended periods. Although this atmosphere is continuously monitored with a real-time, mass spectrometer-based Central Atmosphere Monitoring System (CAMS), the ability to measure trace constituents is limited. The identity, concentrations and distributions of trace constituents have been studied more exhaustively, in some cases for as long as the duration of a patrol, using conventional active air sampling methods such as passivated stainless steel canisters and solid sorbent tubes. The results from these studies indicate that trace constituents are generally present at concentrations well below levels that would present health concerns. However, these studies also show that there is a fairly wide variation in such levels over time, operational conditions, submarine and class of submarine.

The thermal control subsystem design, analysis, and test-verification that made possible the successful Clementine moon-mapping mission was indeed formidable in many respects, with very high ratios of requirements-to-available resources and performance-to-cost/mass, exacerbated by an unyielding tight schedule. Environments, requirements, program restrictions, design highlights, and lessons learned are presented. Emphasis is given to the sensor-bench payload and its unusual thermal components: three types of heat pipes (variable conductance, fixed conductance, and diode), a thermal-energy-storage beryllium block, and a multitude of flexible conducting straps. A description of the thermal design verification test emphasizes its unconventionally and lessons learned. Despite adverse schedule and cost-cutting effects on test hardware, planning, and execution, test data made possible thermal model refinements and important hardware design changes.