International research organization Deep is dedicated to furthering our understanding of "the planet's deep water environments." In a nutshell, what NASA is to space, Deep wants to be for the ocean. To that end, they've designed and engineered this Sentinel subsea habitat. It's essentially an underwater space station:

The Sentinel™ System makes possible a completely new world of subsea living and working. The modular system is endlessly configurable, completely customisable, and flexes seamlessly to accommodate short-term through to semi-permanent deployments, anywhere on the Continental Shelf.

By enabling the manufacture, transport, deployment, maintenance, retrieval and redeployment of modular subsea habitat components, the Sentinel System is at once safe, efficient and economical. And in its completely transformative technology, conceived without compromise on the six Sentinel Design Tenets, the system changes subsea habitation once and for all.

DESIGN TENET #1: Reconfigurability

The Sentinel™ System can be configured at virtually infinite scale, and re-configured between missions without the need to recover to the surface. It is as suited to smaller, six-crew, short-term deployments as it is to 50-crew, multi-nation, semi-permanent research stations. Its components can be configured, re-configured and re-located at depth.

For Sentinel operators, this reconfigurability affords the benefit of being able to tailor a Sentinel span specifically to suit particular tasks, and to re-configure it between – and even during – missions.

DESIGN TENET #2: Pressure-Adapted

The Sentinel™ System has been designed for operation at either one-atmosphere, or at ambient pressure.

One atmosphere operations enable short-visits to Sentinel via submarine transfer, ideal for academics or media professionals without diving qualifications. Ambient operations allow the use of Sentinel's two moonpools for diving excursions, making it perfect for long-form missions by qualified divers.

DESIGN TENET #3: Habitability

The Sentinel™ System features customisable interiors unlike any other subsea habitat. To ensure Sentinel Operators can perform to their very best, DEEP's Human Performance, Human Factors and Dive teams have collaborated on every aspect. This means a great night's sleep, delicious and nutritious food, and a warm and pleasant living environment.

DESIGN TENET #4: Modularity

Key to the Sentinel™ System flexibility and re-deployability are the modularity of systems, components and architecture. Interiors can be re-configured on the seabed; entire sections can be added, removed or re-located without affecting the operation of neighbouring Sentinels. The possibilities are without end.

DESIGN TENET #5: Re-deployability

Sentinels will have a service life of 20 years and can be re-deployed to different locations across the world to maximise their utilisation and optimise their usability.

The ease with which Sentinel systems can be re-deployed provides Sentinel owners and operators the opportunity to work on multiple smaller projects, for which traditional habitats were not viable. The animation above illustrates the ability to move Sentinels across a large area between either fixed or mobile foundations.

DESIGN TENET #6: Surface Independence

DEEP is committed to the complete eradication of the requirement for a financially and environmentally expensive Dive Support Vessel (DSV) stationed on the surface during dive operations.

The Sentinel power systems are based on a micro-grid architecture and are designed to work with DEEP's renewable power and satellite communications buoy. DEEP's Research team are actively developing a large-scale bio-reactor to treat all waste, negating the need for the periodic emptying of tanks.

Deep is currently working to achieve third-party certification for Sentinel.