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Students Visit Aquarius: The World’s Only Undersea Research Laboratory

Wearing the MK 37 SS hard hat, alumnus Scott Van Hoy holds up the APUS Analog Research Group flag during the tank dive. Image courtesy of Aquarius Reef Base – the world’s only undersea research laboratory.

By James Sheffield, Current Student, Bachelor of Science in Space Studies and Scott Van Hoy, Alumnus, Master of Science in Space Studies

Have you ever wondered what it takes to live at the bottom of the ocean? In December of 2022, we got to experience the challenges and rewards of working underwater at Aquarius, an undersea research laboratory off the Florida coast. As members of the American Public University System Analog Research Group (AARG), it was a highly exciting learning experience for both of us.

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Aquarius: An Undersea Research Laboratory

Aquarius Reef Base (Aquarius for short) is an undersea research laboratory and habitat owned by Florida International University (FIU), and it serves as a hotspot for both space and ocean research. It sits about 5.4 nautical miles off the coast of Key Largo, Florida, and 60 feet under the surface of the ocean.

Aquarius serves as the world’s premiere marine research facility, serving marine scientists studying the ocean. However, what is less known is that this ocean habitat is also the best location on Earth to test going to space.

The Sea-Space Connection

Sample collection NASA aquanaut
A NASA aquanaut simulates sample collection during a NEEMO mission. Image courtesy of NASA.

The National Aeronautics and Space Administration (NASA) frequently uses the undersea research lab to train astronauts and test new operations procedures and technologies. NASA’s aptly chosen name for these missions is NASA Extreme Environment Mission Operations (NEEMO).

To date, the Aquarius team has trained 57 astronauts from NASA and other space agencies. After living in the habitat, astronauts earn the title of “aquanaut.”

American Public University System Analog Research Group
These astronauts and aquanauts from the NEEMO 22 mission lived inside Aquarius for 10 days, testing future space technologies and operational procedures. Image courtesy of NASA.

As space studies students and avid divers, we got to see firsthand the sea-space connection and the benefits of utilizing the ocean to prepare for human spaceflight operations. Perhaps the greatest lesson we learned during our week in Florida is that living in the ocean is no easy task.

Taking FIU’s Introduction to Saturation Diving Course

We signed up for an FIU micro credentialed course called Introduction to Saturation Diving: Aquarius Operations and Benefits to Science. This program is part of the Medina Aquarius Program, the overarching program of the Aquarius Reef Base.

Instruction for this course was in Islamorada, Florida, at the Aquarius Shore Base. Our instructors were Thomas Potts, the Aquarius Associate Director of Research, and Roger Garcia, Aquarius Operations Director and Diving Safety Officer. Additionally, there were other members of the the undersea research laboratory team to instruct our class for our safety.

The main purpose of the course was to teach students about the history of undersea habitats and how they contribute to science. We also learned the basics of saturation diving operations, equipment and procedures.

The class kicked off with a flurry of questions from the instructor, testing us on the material we learned during the online section of our course. After we were “thrown to the sharks” with review questions, the class toured the shore base facilities. There was a large recompression chamber, several research vessels and a watch desk with direct links to the undersea research lab for monitoring its conditions.

These facilities provide the logistics and safety capabilities required to operate Aquarius. After the tour, we took a field trip to the History of Diving Museum where we learned about how far diving has come from its inception.

Hard Hat Diving

After the review questions and orientation, we learned hands-on skills required to conduct simulated space missions underwater. The first skill was learning how to dive using a Kirby Morgan (KM) 37 Stainless Steel (SS) dive helmet.

Undersea Research Laboratory Aquarius
James just moments before conducting an open water dive, wearing the Kirby Morgan 37 Stainless Steel dive helmet. Image courtesy of Aquarius Reef Base.

Also called “hard hats,” these bulky helmets are connected to either air tanks on a boat or to areas inside the Aquarius habitat, allowing aquanauts to have a constant supply of air. The hoses that connect the aquanaut to the air supply are collectively called the “umbilical.” In addition to providing a diver’s air, the umbilical also houses communications lines, allowing crew members to talk to each other while they are underwater.

American Public University System Analog Research Group AARG
The KM 37 SS hard hat is used by NASA to simulate space walks underwater. Image courtesy of Aquarius Reef Base.

NASA uses hard hat diving during NEEMO missions to simulate Extravehicular Activity (EVA), more informally called space walking. Due to the aquanaut’s buoyancy in the water, the low gravity conditions of walking on either the Moon, Mars or an asteroid can be closely replicated.

We spent three days learning how to use the KM 37 SS helmets, taking a “crawl, walk, run” approach. Instruction began in our shore-based classroom, where we learned about the different components of the dive system.

Later, we practiced using the helmet in a “dive tank,” which is essentially an above- ground pool with a window to view divers. Finally, we loaded our equipment onto the RV Bond research vessel and the class participated in an ocean dive wearing the helmets.

Undersea Research Laboratory Aquarius
James preparing for a hard hat dive on board the RV Bond. Image courtesy of Aquarius Reef Base.
American Public University System Analog Research Group AARG
Scott preparing for a hard hat dive on board the RV Bond. Image courtesy of Aquarius Reef Base.
Undersea Research Laboratory Aquarius
James, Scott and two other Intro to Saturation Diving students, Dr. Rachel Moore and Bader Al Moulah, posing in front of Aquarius Reef Base. Image courtesy of Aquarius Reef Base.

The Habitat and Saturation Diving

The next phase of the course was learning about living in the underwater habitat. Aquarius is a complex life support system that allows humans to live on the bottom of the ocean, but living there is not without its risks.

After aquanauts spend 24 hours inside the undersea research lab, they are considered to be “saturated,” meaning the tissues in their bodies contain higher levels of nitrogen due to the increased pressure at the bottom of the sea. In our class, we learned about how the higher level of nitrogen impacts the human body and mission operations.

The most notable lesson was that once saturated, aquanauts can’t come back to the surface right away or they’ll get decompression sickness (also known as caisson disease or “the bends”). Removing the excess nitrogen from the body takes almost a full day of decompression, allowing the excess nitrogen to slowly leave before it is safe to come back to surface pressures.

After a review of saturation diving and habitat systems, our class took a 45-minute boat ride to Aquarius and prepared to dive down to the habitat. Led by Roger Garcia, the class and several members of the the undersea research laboratory team swam down to the undersea lab for our orientation.

Undersea Research Laboratory Aquarius
Several students and Aquarius staff members diving down to the habitat in the open ocean. Image courtesy of Aquarius Reef Base.

We entered Aquarius through the “wet porch,” an aft room that allows divers to enter through a large opening where the inside air pressure equals the outside water pressure, preventing water from inadvertently flooding the undersea research laboratory. Our class then had an hour inside the habitat before we reached the no-decompression limit. This limit is the time when going immediately back to the surface is no longer an option without allowing extra time to enable the nitrogen building in our tissues to leave our bodies.

Undersea Research Laboratory Aquarius
The back side of Aquarius is called the “wet porch” and is where divers enter the habitat. Image courtesy of Aquarius Reef Base.

The inside of this undersea research laboratory is small, only about the size of a school bus. It made orientation quick, giving our class time to enjoy the view out the window. We even made a quick video conference call to other members of AARG.

Undersea Research Laboratory Aquarius
James, Scott, Rachel, and Bader viewing all of the fish and coral that make up the ecosystem around Aquarius. Image courtesy of Aquarius Reef Base.

After we spent time inside Aquarius, Roger took the class around the outside of the habitat. He pointed out some of its key engineering features, as well as a few fish.

American Public University System Analog Research Group AARG
James, Scott and Rachel diving on the outside of Aquarius Reef Base. The undersea research laboratory has been in the water long enough that it has become a living reef with plenty of coral and fish. Image courtesy of Aquarius Reef Base.

Practicing for Emergency Situations in Aquarius

During the second day of diving at Aquarius Reef Base, we were told to brush up on our emergency procedures and be prepared to practice for problems that can occur while aquanauts live in the habitat. Fire, flooding and power loss are all potential issues aquanauts face in Aquarius.

We geared up and dove down to the habitat. Shortly after we entered Aquarius, Roger yelled, “THIS IS A DRILL! THIS IS A DRILL! THIS IS A DRILL!”

He explained to everyone that they were all in simulated saturation and we needed to evacuate Aquarius quickly due to a catastrophic failure of the life support system. The evacuation involved teamwork from the students and the Aquarius staff to practice for this worst-case scenario.

To safely bring aquanauts back to the surface after they are saturated, they need to quickly leave Aquarius, swim to the surface and enter a recompression chamber within 10 minutes to bring their bodies back to the depth of Aquarius. Our research boat had a Transportable Recompression Chamber System (TRCS) that allows this rapid recompression, preventing the onset of decompression sickness.

Undersea Research Laboratory Aquarius
Roger looks into the small porthole to check up on the students as a Dive Medical Technician operates the TRCS. Image courtesy of Aquarius Reef Base.

Two Aquarius staff members dove down to aid the class, simulating saturated aquanauts, in the evacuation of the undersea research laboratory. The class then entered the very tight TRCS with a Dive Medical Technician (DMT) and embraced the uncomfortable boat ride back to shore.

Once we were back on shore, our class was transferred to a 72-inch shore recompression chamber. In a real emergency, aquanauts would spend 16 1/2 hours decompressing in this chamber. However, we only spent 20 minutes in the chamber to allow the DMTs to practice operating the system and provide us with the unique experience of a “chamber ride.”

Overall, the class and the Aquarius performed well during this simulated emergency, meeting the strict criteria needed to ensure a safe outcome for everyone. After we left the recompression chamber, we graduated from the course and received our certificates of completion.

Undersea Research Laboratory Aquarius
James, Scott, Rachel, Bader and Aquarius team pose for a class portrait, celebrating their successful completion of the first public access Introduction to Saturation Diving course at Aquarius Reef Base. Image courtesy of Aquarius Reef Base.

AARG and Continuing Our Partnership with Aquarius

In the future, we hope to continue the partnership between Aquarius Reef Base and AARG. In the past, AARG members have uses space analog facilities such as the University of North Dakota’s Inflatable Lunar/Mars Analog Habitat and the Mars Society’s Mars Desert Research Station to conduct research on human spaceflight topics. Aquarius provided us with an excellent space analog environment for University students to conduct research and technology capabilities tests in the future.

If you are a University student or faculty member and you are interested in being part of AARG, send an email with your interest to

About the Authors

James Sheffield is a current student at American Military University, pursuing a bachelor of science in space studies. He is a member of the Golden Key International Honour Society, the SALUTE Veterans National Honor Society and AARG. James is also a Senior Staff Instructor for the U.S. Army.

Scott Van Hoy received his master of science in space studies from American Military University in 2022 and is a founding member of AARG. Scott earned a bachelor of science in atmospheric sciences and a master of science in technology management from the University of Illinois Urbana-Champaign and is currently earning a Ph.D. from Capitol Technology University. He is an aviator for the U.S. Navy.

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