An NBRF diver wearing the MARS space suit works on a model of the Hubble Telescope,
assisted by the Ranger robot.

Neutral buoyancy is one of the primary ways we can simulate weightlessness on earth. When an object is put underwater, and the right amount of floatation is added so it neither sinks nor rises, it behaves as if it were not subject to gravity. For this reason, neutral buoyancy has been used to train astronauts and develop equipment used in space.

The Only Neutral Buoyancy Facility on a College Campus

The University of Maryland's Neutral Buoyancy Research Facility (NBRF) is one of four on-campus research sites associated with the Space Systems Laboratory. It is one of only three operating neutral buoyancy tanks in the United States, the only one located on a college campus, and the only one dedicated to research. At 50 feet wide and 25 feet deep, it is large enough to accommodate equipment, robots and people engaged in research dedicated to making it easier and safer to work in space.

To explain how such a rare facility ended up at the University of Maryland is to tell the story of its director, Dr. David Akin. It begins at the Massachusetts Institute of Technology (MIT), where the Space Systems Laboratory was founded in 1976. When Akin began his neutral bouyancy research, the only facility available to his team was MIT's swimming pool—and they were only allowed to use it on Saturday nights! But by 1990, Akin's body of research convinced NASA to award him a grant to build a dedicated neutral bouyancy tank. With no place to put it on MIT's already full, urban campus, Akin moved the Space Systems Laboratory to the University of Maryland, which leapt at this unique opportunity to expand its aerospace engineering program. By 1992 the tank was built and the Neutral Bouyancy Research Facility was in operation.

A Sampling of Specific Projects

The Ranger robot working on a mockup of the Hubble Telescope. The Ranger is much larger than even a big picture implies—fully extended it stands 24 feet tall, and has a 30-foot arm span!

The NBRF's research centers around the principle that the best way to work in space is to team astronauts with robots. Humans are experts in real-time decision making and manual dexterity, while robots are more capable of repetitive, stength- and precision-oriented activities. Depending on the task, studies have shown a human-robot team can increase efficiency from 50-500% over human-only work.

To this end, the NBRF has been engaged in the design and testing of robots, equipment, and spacesuits, as well as the study of human factors in space. Perhaps its best-known projects have involved the spaceflight-qualified Ranger series of robots, which were designed to repair satellites, prepare work sites and act as servicing systems for the Hubble Telescope and International Space Station. The NBRF has also developed the Maryland Advanced Research/ Simulation (MARS) space suit, which is used to study human/robot interaction and simulate astronauts' working conditions.

The Space Systems Laboratory and NBRF will adapt its dexterous robotic technology to fit on SEABed, the vehicle designed by the Woods Hole Oceanographic Institute to explore life at the ocean floor's hydrothermal vents.

Currently, the NBRF is working with the Massachusetts-based Woods Hole Oceanographic Institute under NASA's Astrobiology Science and Technology Experiment Program (ASTEP). Their goal is to develop a team of autonomous robots capable of exploring and gathering the unusual life forms at the deep-sea hydrothermal vents 4000 meters below the polar ice caps. The conditions these robots will face are similar to those on Europa, one of Jupiter's moons, and could set the stage for searching for life there and beyond. (Learn more about the ASTEP Project.)

Although the NBRF most often collaborates with NASA and government agencies, it sometimes teams up with industry and academia. It has worked with spacesuit manufacturer Hamilton Sundstrand, and Cis-Lunar, which develops underwater life support and diver propulsion equipment. It is also involved in a project with Georgetown University, which will translate assisted-movement systems for astronauts into exoskeletons that can be used for physical rehabilitation.

Student Involvement

The NBRF provides excellent opportunities for engineering students, especially undergraduates, through capstone projects or employment at the facility. Rising engineers can put their education to work in building, repairing and maintaining the equipment. And not everyone involved is in aerospace engineering—the Department of Mechanical Engineering's undergraduate Human-Powered Submarine Team has tested its submersibles in the NBRF's waters. K-12 students often come for tours, and Women In Engineering has conducted projects involving the tank with its 9th and 10th grade participants.

For more information, visit the Space Systems Laboratory site.
For amazing, high-resolution underwater photography and movies of the tank in action, visit the Space Systems Laboratory Photographic Archives. 

Two of the human-powered submarines developed by mechanical engineering students:
The Terpedo (above), and the RSR Fourier (below).