Written by
Tom Potts
Associate Director of Habitat Operations
April 16, 2026
DEEP recently revealed its pilot subsea human habitat, Vanguard, will be deployed at Tennessee Reef in the Florida Keys National Marine Sanctuary.
It is the first underwater habitat built in the United States in 40 years.
The previous habitat was NOAA’s Aquarius Reef Base, redeployed in Florida in 1993 – an operation I remember well as part of my 30 years involved with Aquarius.
I was Program Director of NOAA’s National Undersea Research Center. Now, having been involved in that segment of undersea history, I’m involved in the next chapter of undersea living with Vanguard.
Vanguard is an incredible tool for science. Time underwater used productively can help us answer meaningful questions and address real issues.
And a critical ingredient in the recipe for research success is where an underwater habitat is deployed.
Selecting a location for Vanguard’s deployment was a complex and meticulous process involving many different experts across DEEP. Here’s how and why we settled on Tennessee Reef for Vanguard.
The Florida Keys were a natural choice for DEEP’s pilot habitat. The Keys are an iconic underwater landscape, home to a rich and diverse ecosystem that holds immense value for research and conservation efforts.
The region already has a strong legacy of underwater research, notably through the Aquarius program, which demonstrated the value of the long-term study of reef systems. It’s a proven environment for this kind of work.
Florida offers excellent infrastructure and an established research community, both of which support and shape scientific activity from an underwater habitat.
The warm, tropical waters make year-round diving for aquanauts feasible, adding a practical advantage to the location.
But how do you go about selecting a precise deployment site within the Keys?
Site selection begins broadly and is then systematically refined to a small number of viable locations.
It’s a complex process involving multiple disciplines and extensive permitting – for both operations and deployment – as well as engineering considerations that vary depending on the site, such as depth and seabed composition. Close collaboration with the Florida Keys National Marine Sanctuary is essential throughout and we are fortunate to have an incredible relationship with the team at NOAA responsible for managing the sanctuary.
There are many variables we had to consider when selecting a location for Vanguard. There were five key criteria, however, that were most important in identifying a suitable deployment site:
The site had to allow controlled access to protect research activities and ensure the safety of aquanauts. Controlled access is critical for two reasons: it prevents interference with long-term experiments and equipment, and it ensures safe operations by limiting interactions with recreational divers and boat traffic. While we absolutely want to engage with the wider dive community, this must be managed in a structured and safe way. Being within a conservation area provides the legal framework needed to restrict access to an area for effective scientific research and operational safety.
The site needed to maximize research and conservation value. This means being close to coral reef systems and a depth profile suitable for a range of studies, ideally around 18 m (60 ft), with areas extending to 21-27 m (70–90 ft) or deeper.
The habitat needed to be installed in an area free from sensitive marine resources, avoiding damage to reefs and other ecosystems. Comprehensive benthic surveys were undertaken to ensure deployment will not harm sensitive marine life or disturb coral.
Astable sand plain is required to support and secure a habitat. The site needs to provide sufficient space for deployment. Each specific site comes with its own engineering challenges, so it’s a collaborative effort to evaluate potential sites and understand the design and engineering requirements.
The site must be close to a shore base to support logistics, emergency response, and aquanaut training. This presents its own challenges, as suitable facilities with the required space and access to deep water are limited in the Keys.
Under these assessment criteria, Tennessee Reef emerged as a frontrunner for Vanguard’s deployment.
Tennessee ReefConservation Area, located 7.4 km (4.6 nm) south of Long Key, is closed to entry. By limiting this site to research only, as well as ensuring safety, scientists will be able to differentiate impacts caused by resource use and those caused by changing environmental condition, while promoting sanctuary management or recovery of sanctuary resources.
Tennessee Reef is a distinctive site. It’s a coral reef habitat containing a deep spur-and-groove system with unique deepwater, slow-growth corals and sponges.
The precise deployment site is strategically located to be a short distance from the upper limits of mesophotic or twilight zone coral ecosystems 30-150 m (100-500 ft). This area is an important biodiversity reservoir providing refuge for species impacted by climate change and storms, representing enormous potential for research.
The reef starts within meters of Vanguard and aquanauts will be able to directly explore a shallow portion of the ocean, 17-20 m (55–65 ft), and another deeper spur-and-groove area starting at 22m (72 ft).
Vanguard's foundation sits on the seabed at a depth of 17 m (56 ft). The living chamber is attached atop the foundation at a depth of 13 m (42 ft), making it ideal for using air as a breathing medium. This deployment arrangement is advantageous as there are proven protocols and dive tables vetted by the US Navy, NOAA and others.
Vanguard’s location is a short boat ride from DEEP Station Florida, a well-equipped shoreside base in Marathon, supporting habitat control, aquanaut training, and emergency response.
So what exactly might be achieved from living underwater in Tennessee Reef? The potential opportunities are as broad as they are exciting. Here are the top activities most likely to supported from Vanguard:
