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Neutral Buoyancy Research Facility (NBRF)

Brief Mission

The NBRF is one of two currently operating neutral buoyancy tanks in the US. It is the only one in the world located on a college campus, and the only one dedicated to basic research. Neutral buoyancy is one of the primary means of simulating the microgravity environment of space; while the NBRF was originally developed to support NASA studies of orbital operations, it is also actively used for underwater robotics and both human and robotic operations in simulated lunar and Mars gravity. Related research in the Space Systems Laboratory (SSL) emphasizes space, undersea, and medical rehabilitation robotics; space human factors, including bioinstrumentation and advanced space suit design and testing; human-robot collaboration technologies; and the underlying fundamentals of space simulation. 

Hours of Operation

Monday through Friday, 9 AM to 4:30 PM; alternate times by arrangement. The NBRF has the capability to conduct night tests (no ambient lighting) if required.

Services and Technologies Offered

The neutral buoyancy tank is 50 feet across, 25 feet deep, and holds 367,000 gallons of water. Water temperature is maintained at 88°F for consistency of buoyancy and comfort of test support divers, and is specially filtered for maximum visual clarity.

The facility allows external access for underwater test hardware up to 15 feet on a side and up to 4000 pounds in weight. Complete SCUBA diver support facilities include two locker rooms, air compressors for filling SCUBA bottles, and both underwater speakers and bidirectional underwater communications system. A secure storage facility for underwater test hardware is located outside the NBRF for hardware which will not be damaged by exposure to the elements.

There are currently six robots operational in the NBRF, including two generations of Ranger, a four-armed satellite repair robot; two SCAMP vehicles and EUCLID, all 6 degree of freedom free-flying underwater vehicles used as camera platforms and for advanced control algorithm development; and SAMURAI, a 6000-meter rated deep ocean electrical dexterous manipulator for autonomous underwater operations. The NBRF is equipped with a 16-camera Qualisys motion tracking system capable of providing measurement of the location and velocity of an essentially unlimited number of optical targets at submillimeter accuracy and less than 100 msec sample times. The robotic manipulator systems are also capable of operation in the laboratory environment, allowing simplified checkout and correlation between underwater and laboratory simulations.

The SSL has developed two series of human-rated suits for simulation of extravehicular activity underwater. The MX-2 system is a full pressure suit, operating at 3.5 psid and providing a dry environment for the wearer with high fidelity to flight-rated pressure suits. This suit has been equipped with a variety of bioinstrumentation for measuring body motions and metabolic workload, as well as advanced controls and displays for immersive virtual reality presentations as part of the underwater simulation. A parallel series of space suit simulators provide a lower-fidelity experience of suited operations, but provide low-cost simulations without excessive training requirements for the test subject. Wearers of the MX-C/MX-D series of suit simulators are immersed in water, and effectively supplied by conventional scuba equipment within the suit envelope. Other human test systems available at the NBRF include a body harness for body segment parameter ballasting for realistic simulation of partial gravity environments such as the moon and Mars, and an underwater treadmill for studying gaits and workloads.

A small but very well-equipped machine shop on-site is used to fabricate and repair test equipment, with both manual and computer guided mills and lathes, sheet metal forming capabilities, and TIG welding equipment. The SSL also has access to rapid prototyping capabilities and the well-equipped machine shop of the Clark School of Engineering.

The NBRF control room is used for conducting tests in the neutral buoyancy tank. The control room has four general-purpose workstations that are used to control robots underwater through Space Shuttle-style hand controllers or a virtual reality interface, as well as providing multiple user-selectable video views from cameras in and above the tank. A multichannel communications system allows test conductors to talk with divers underwater, with personnel throughout the NBRF, and with other sites across the country through the Internet and satellite links. The control room also houses a complete video control and editing suite, and is capable of sourcing live video feeds for broadcast purposes.

Equipment Available

  • 50 ft. diameter x 25 ft. deep neutral buoyancy water tank
  • Standard diving equipment: regulators with octopus and buoyancy control devices
  • AGA full-face masks for two-way communication
  • 25 ft. hookah rigs for externally mounted or surface-supplied air
  • Underwater handling equipment (lift bags and rigging straps)
  • 2-ton overhead wirelessly controlled hoist
  • Diver locker rooms, scuba prep area, water ingress/egress platform
  • 12 wall-mounted hard points for securing test hardware
  • Two underwater remote pan/tilt/zoom cameras controllable via internet
  • Numerous underwater video cameras with live feeds
  • High resolution underwater still and video cameras for documentation
  • 32x32 video crosspoint switching system
  • Video recording in Betamax, VHS, Hi-8, digital tape, and direct-to-media digital stream
  • 24-channel audio mixing board
  • 12-channel audio intercom system
  • Wired and wireless audio belt packs
  • 16-camera Qualisys underwater motion tracking system
  • Three Ranger NBV dexterous robot arms (6-7 DOF x 1.5 m length)
  • Two Ranger TSX dexterous robot arms (10 DOF x 1.5-4 m length)
  • Ranger PXL positioning manipulator (6 DOF x 2.5-10 m length)
  • SAMURAI 6000 meter depth-rated manipulator (6 DOF x 1.25 m length)
  • Two SCAMP free-flying camera platforms
  • EUCLID free-flying space simulation vehicle
  • MX-3 pressurized space suit (under development)
  • Two MX-C space suit simulators
  • MX-D hard-suit space suit simulator (under development)
  • Video/audio control, routing, recording, and broadcast station
  • Four software-configurable general purpose robot control stations
  • Conference and test monitoring room
  • Machine shop


Basic facility rental is $2500/day, which includes Space Systems Laboratory personnel supporting surface activities and conducting underwater test support. Dive personnel from outside entities can be certified to dive in support of test operations, but this requires extensive training and certification as well as physician health exams. Organizations interested in supplying dive personnel should contact the NBRF no less than two months prior to testing.


Dr. David Akin
382 Technology Drive, College Park, MD 20742
Contact Email:
Contact Phone: (301) 405-1138

Facility URL

Neutral Buoyancy Research Facility

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