Core Research and Capabilities

The submarine is one of the most physically and mentally challenging platforms in the U.S. Navy, where submariners work, sleep, eat, and play in the same environment for extended periods. Lack of natural sunlight, disrupted circadian rhythms, challenging watch schedules, limited access to physical exercise, and reduced availability of fresh produce are some of the factors that may affect submariner health and performance during long deployments. NSMRL has initiated multiple efforts to understand how the undersea environment affects Sailor health and performance. These efforts include: the creation of the Unobtrusive Performance Measures Lab to measure human performance in real-time and under various conditions without the interference of intrusive technology, development of a team task simulation bridge to assess real-time team dynamics during virtually created bridge operations, and implementation of studies on the effects of the submarine environment and lifestyle on submariner performance and physiology.

Submarine atmospheric monitoring research at NSMRL is composed of both the Submarine Atmosphere Health Assessment Program (SAHAP) Program of Record, which provides ongoing atmospheric monitoring support, and independent research on developing new monitoring technologies. During underway periods, submariners are in a closed environment, requiring close monitoring of the atmosphere to ensure that it does not pose a hazard to the crew. While automated systems continuously measure levels of the most critical gases, including O2 and CO2, other possible contaminants, such as oil particulates or organic compounds produced by machinery, must also be monitored on a long-term basis. As one of the Navy’s primary resources to ensure the safety of the submarine atmosphere, SAHAP provides long-term, passive monitoring for defined atmospheric compounds of concern while underway. The program also provides guidance on the effects of evolving technology that could affect the submarine environment, such as the emittance of nanoparticles from 3D printers. Additional NSMRL research related to atmosphere monitoring is focused on exploring the use of personally worn passive dosimeters to determine individual exposures to environmental contaminates in the submarine atmosphere while underway.

Divers are among the most highly trained, highly skilled Navy Sailors, and are critical for the protection, safety, and success of our submarine and surface fleets. While the divers work to protect us, NSMRL’s underwater bioeffects team works to protect them. The team conducts human effects research and provides guidance to the fleet on how underwater sound and blast from sources such as sonar, tools and equipment, and impulse sound affect human divers. Their work on underwater sound detection and localization and hearing in hyperbaric conditions has led to advancements in our understanding of the underwater hearing abilities of humans, with NSMRL researchers being the first to document that humans can detect underwater sounds as high as 190 kHz. NSMRL translates research findings into evidence-based guidance for diver exposure to underwater sound and blast. Research focuses include: physiological mechanisms for underwater sound perception, diver protection from underwater sound and blast, the use and effectiveness of underwater sound in nonlethal diver deterrence systems, creation of physical and computational models of physiological response to underwater sound, and development of tools and guidance for underwater hearing conservation.

Submariners face significant stressors that are unique among the military community. The confined space and isolation of the submarine can be mentally and emotionally challenging, and yet mission success depends on optimal psychological readiness of Sailors. NSMRL’s psychological screening and fitness program is dedicated to improving the psychological suitability of prospective submariners, predicting and reducing the number of unplanned losses (unexpected separation from service) from operational units, and exploring and enhancing individual and team resilience. NSMRL has an ongoing effort to maintain, administer, and score the psychological screening assessment for prospective submariners. This assessment process, known as SUBSCREEN, seeks to identify Sailors with psychological and/or motivational factors incompatible with submarine duty. NSMRL is also conducting studies to define the ideal psychological profile for successful service in submarines and other nuclear-powered Navy platforms and strives to support the psychological fitness of submariners by providing mental health support tools for use while underway.

With the emergence of new submarine technologies, Sailors are increasingly required to process complex information, make advanced decisions, and operate complicated equipment. Human Systems Integration (HSI) is a process NSMRL researchers use to provide tools to present information in an accessible manner, assist in decision making, and facilitate usability of hardware and software technologies. HSI combines our knowledge of human capabilities and limitations with systems development to make them more effective, efficient, and safe. By combining theory with an iterative feedback process with the line community, NSMRL applies an HSI approach to develop and improve submarine systems, enhance submariner performance, and increase readiness. The program also seeks to predict and mitigate degradation in performance through noninvasive monitoring of a variety of novel physiological measures.

NSMRL’s diving and hyperbaric research program focuses on evidence based solutions that promote the health and enhance the performance of the undersea warfighter. At the centerpiece of NSMRL’s diving and hyperbaric research program is the one-of-a kind Genesis Hypo/Hyperbaric chamber complex. NSMRL’s diving mission is supported by a full Navy dive locker with SCUBA and Surface Supply capabilities, an indoor immersion test pool, and a command dive boat for open water diving operations. NSMRL’s diving research program has advanced the field’s understanding of saturation diving, nitrogen narcosis, CO2 toxicity, pulmonary O2 toxicity, decompression stress, NO physiology under ambient pressure extremes, temperature regulation, and disabled submarine escape and survival. In addition, it has provided knowledge about the environmental stress diving can have on warfighter health, cognition, and performance. A complete renovation of the chamber was initiated in 2019, with expected completion in 2022. As a result of the overhaul, NSMRL will have a fully-functional, state-of-the-art chamber facility to advance diving and hyper/hypobaric medicine research.

In the rare event that a submarine becomes disabled and is unable to return to the surface (DISSUB), the crew must decide whether to remain onboard and await rescue or escape from the vessel. This decision rests on a complex set of factors including condition of the crew, the status of the submarine atmosphere, depth, and proximity of rescue assets. NSMRL maintains military and civilian expertise in submarine survival, escape, and rescue to provide NAVSEA 00C and SUBFOR fleet advice in case of a DISSUB incident. Areas of research focus include: DISSUB survival (e.g., survival times and survival equipment evaluation), DISSUB escape (e.g. saturation decompression drop out modeling, escape suit testing, medical hazards of escape), rescue procedures and equipment testing (e.g. test and evaluation of closed circuit O2 rebreathers for accelerated decompression of DISSUB survivors), and science-based recommendations to modify the GUARD Book, the manual that gives guidance to survivors of a submarine casualty.

Noise-induced hearing loss is one of the most prevalent occupational health hazards in the military. To help protect our service members’ hearing, NSMRL’s Regional Hearing Conservation (RHC) Program of Record (POR) provides subject matter expertise on hearing conservation, psychoacoustics, audiology, and hearing protection to the Navy and Marine Corps line communities. The program also provides support to Navy audiologists, otolaryngologists, allied health professionals, audiometric technicians, and consultants across the DoD and Defense Health Agency. NSMRL houses an expansive state of the art audiology test suite that includes one of the largest anechoic chambers in the DoD, a large reverberant room, a Real-ear Attenuation at Threshold (REAT) facility, and multiple audiology test booths. RHC POR efforts include basic to applied research. The team’s principal investigator is a member on multiple American National Standards Institute (ANSI) working groups related to speech-in-noise understanding and assessing the effects of head-worn devices on human auditory localization ability.

This unique program maintains an epidemiologic database that cross-references a number of Navy data sources and aids in characterizing the health effects of the submarine and diving environment. With the ability to provide rapid analysis, the program can serve as a reference source for operational planning and risk mitigation. As part of this program, NSMRL initiated the first-ever epidemiological study to evaluate the medical impacts of the submarine environment on Sailors. The program recently expanded its research to include divers to assess the impact of the undersea environment on diver health. UHERP’s main objectives are: to identify any environmental or occupational exposure risk that correlate with negative health outcomes, premature separation from military service, medical evacuations, and to improve the health and warfighting capability of the undersea warfare community by harnessing information from “big-data” platforms.