One of the biggest challenges in astronaut training is learning how to perform tasks in low gravity environments. Buoyancy, which is the ability of an object to float in liquid, such as water, is the reason that aquanauts are able to simulate low gravity. Normally, the crew members would be positively buoyant, meaning that they would float in the water. However, by wearing diving equipment and weighted backpacks, aquanauts are able to work on the ocean floor with only minimal positive buoyancy. This way, NEEMO missions can include practicing extravehicular activities (EVA) and imitate "spacewalks" to test concepts for mobility in low gravity.
The NEEMO 15 mission will provide crew members with multiple opportunities to interact with DeepWorker submersibles, one-seater submarines that are analogues for Space Exploration Vehicles. They will collaborate to test exploration, protocol, and communications techniques in a Near Earth Asteroid (NEA) simulated environment.
Crewmember health is of utmost importance when planning for space exploration, especially for long duration missions. Since the first NEEMO mission, a key focus for every aquanaut crew has been physiological and psychological health. Studies have included how their environment affects sleep and the body's immune system, growth of bacteria within the habitat, nutrition and exercise-related studies.
In addition, coping with medical emergencies without a hospital or trained doctor can be a difficult and dangerous task. Aboard the Space Station and during long duration missions in the future, crew member health and mission success may depend on the crew's ability to deal with emergencies without the help of a doctor. Because of its physical and psychological isolation on the floor of the Atlantic Ocean, Aquarius provides the most accurate stresses needed to validate new telemedicine in an extreme environment.