specialized cables, light sources in electro-optic modules, and photo 

 detector modules. 



As USN equipment and systems are required to operate in ever-in- 

 creasing depths, electronic circuits are called upon to operate at ever 

 greater pressures. The conventional protection for systems at 20.000-foot 

 depths requires an advanced-technology, pressure bottle design with 

 heavy walls and endbells and special electrical feedthroughs. The high 

 cost of this type of protection and the unreliability of the high-pressure 

 seals have prompted the USN to initiate the Pressure Tolerant 

 Electronics (PTE) program to determine the feasibility of employing 

 solid state circuits in a "wet" environment without pressure protection. 



PTE circuits can be effectively used on any system operating beneath 

 the sea surface. These liquid-filled, automatically compensated designs 

 are potentially more reliable and easier to fabricate than pressure proof 

 containers, even for shallow depths. 



The goal of the PTE project is to develop and verify technology for 

 the design of PTE systems. This goal includes the identification of tech- 

 niques for the fabrication of PTE components and the establishment of 

 guidelines and test procedures to guide system designers in the selection 

 of active and passive PTE components and compensating fluids. Since 

 the project was initiated in 1970. hundreds of devices have been tested 

 including most of those likely to be used in PTE systems. 



MANNED UNDERSEA ACTIVITIES 



The MUST Office in NOAA has continued its role of supporting 

 civilian undersea operations directed to achieving a better understand- 

 ing, assessment, and use of the marine environment and its resources. 



MUST supports NOAA investigations involving marine resource and 

 environmental problems for which manned, subsurface observations, 

 and data collection are required. In addition, MUST has continued 

 assessing the civilian Federal agency needs for submersibles and 

 habitats, and it coordinates the use of available commercial and Navy 

 assets by civilian Federal agencies. Such coordination has included the 

 use of available undersea shallow water platforms for scientific projects 

 jointly sponsored by NOAA and other Federal agencies including USGS, 

 U.S. Army Corps of Engineers, Environmental Protection Agency. 

 Energy Research and Development Administration (ERDA), and Na- 

 tional Aeronautics and Space Administration. In another cooperative 

 effort, the USN, NSF, and NOAA have funded the operation of the deep 

 research submersible Aivin, operated by the Woods Hole Oceanographic 

 Institution under the aegis of the University National Oceanographic 

 Laboratory System 



NOAA supported the use of the Perry Hydrolab near Freeport on 

 Grand Bahama Island in a Bahama Banks Research Program involving 



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