The article was prepared for the 1998 Annual Meeting of the Marine Technology Society, held in Baltimore, Maryland.
Craig Cooper, Jim Buckley, and Jay Styron
NOAA’s National Undersea Research Center at the University of North Carolina at Wilmington
515 Caribbean Drive, Key Largo, Florida 33037.
The Aquarius underwater saturation laboratory is owned and funded by the National Oceanic and Atmospheric Administration’s (NOAA) National Undersea Research Program (NURP). Aquarius is operated by the University of North Carolina Wilmington (UNCW), which is one of NURP’s six regional program centers. Aquarius currently operates in the Florida Keys National Marine Sanctuary; 22 missions were conducted between 1993 and 1996. After refurbishment and recertification, Aquarius 2000 operations began again in 1998 and are planned to continue through at least 2001. A full mission year is scheduled for 1999, and projects are already booked into 2000. Aquarius first operated between 1988 and 1989 in the US Virgin Islands, where 12 missions were conducted. The major change in operations in the Aquarius 2000 program involves a shift from substantial offshore surface–based dive support of missions to more reliance and responsibility for operations by the aquanauts. This is reflected in deployment of the new semi–autonomous Life Support Buoy.
A 100 foot by 50 foot catamaran style barge was used for the initial launch, recovery, and transport of Aquarius in the Florida Keys. Four 35 ton davits raised and lowered the habitat to and from the ocean floor through a moonpool. After deployment off of Key Largo four vans were added to the barge to house life support equipment and to provide a base for the support crew. In its modified form, the barge was referred to as the Mobile Support Base (MSB).
The MSB supported multiple functions, including a platform for support of scientific research, Aquarius day–to–day mission operations, and rapid response in the event of an emergency. The MSB contained the watch desk van, the life support van, the dive locker/lounge van, and recompression chamber van. The MSB was moored directly above Aquarius and was connected to the habitat by multiple hoses and lines bundled together into one unitized umbilical. The umbilical provided Aquarius with electrical power, compressed air, treatment gases, potable water, environmental monitoring and control, video, and communications. Life support functions for six aquanauts could be maintained for 72 hours without surface support, with decompression from saturation depth requiring only 17 hours.
The Watch Desk was manned 24 hours a day during missions and was the nerve center for all communications, direction, and control of routine and emergency operations. The Watch Desk contained VHF radios, sound–powered telephones connected to Aquarius and the chamber van, a hailer, environmental and life support system monitors, four video monitors, the decompression control station, a radar unit, and a cellular telephone. An electronics shop and small science laboratory were also located in the watch desk van.
The life support van contained the environmental control unit, low pressure compressor (Quincy 5120 with 20 HP electric drive), two high pressure compressors (Ingersol 3OT with 20 HP electric drives), reverse osmosis desalinization unit, Haskel gas transfer pump, high pressure gas storage flasks, workshop, and tool storage area.
The dive locker/lounge van contained a dive equipment repair bench, scuba tanks for support divers and aquanauts, diver support equipment, storage space for individual dive equipment, and a small lounge. The recompression chamber van was located on the bow of the MSB and contained a six place, 72 inch, double–lock recompression chamber.
Power for Aquarius and the MSB was provided by two 100 kW Caterpillar 3208 powered three–phase Lima generators. While power was generally regarded as clean and reliable, computers and scientific equipment were protected by surge protectors and UPS systems. Potable water was created by a reverse osmosis desalinization unit in the life support van and was stored in two holding tanks. A sanitation holding tank and treatment system was located on the deck of the MSB. Waste from Aquarius was pumped to the holding tank and then treated to meet Coast Guard Type II Standards.
The MSB was manned 24 hours a day during saturation missions, and operated with twelve support staff: four each on two shifts during excursions, three during the off shift, and one inside Aquarius.
After three years of operation at Conch Reef, Aquarius was retrieved and refurbished in 1996 and 1997. The MSB configuration was dropped in favor of a semi-autonomous buoy. Adopting a Life Support Buoy (LSB) instead of the MSB reflected a shift in operating philosophy that 24 hour surface–based support during Aquarius missions was not necessary. The LSB (a 10 meter discus buoy), was provided to the program by NOAA's National Data Buoy Center, which substantially contributed to the advancement of the Aquarius 2000 concept. A new RF–based communication system (Wave Wireless Networking) was installed on the LSB along with a computer network that links Aquarius, the LSB, and the shore–based watch station. The LSB computer is networked via a LAN to two computers located in Aquarius. All of the computers allow audio and video teleconferencing, with the capability for exchanging graphics and text documents, and a continuous display of life support system data on the buoy and in the habitat via sensors connected to various equipment. The buoy computer is connected to a wireless ethernet LAN that provides point–to–point connection with shore. Internet access and e–mail are also available to the aquanauts through the network, and a cellular telephone operates from inside Aquarius too.
The life support systems contained on the LSB include two high pressure four stage air cooled compressors (Compair Mako 18.7 cfm) and a Haskel gas booster pump, which is used to transfer treatment gases or replenish oxygen flasks on Aquarius. The environmental control unit (mini–chill unit) is located inside a pressure attached to the Aquarius baseplate. Five high pressure gas storage flasks are mounted under the habitat. The recompression chamber is now located at the shore base. As a result, new operational (emergency) procedures and tables have been developed for emergency situations.
The LSB also contains two 40 kW Northern Lights generator sets. The two diesel driven gensets are connected by a manual bus transfer switch that allows startup of the second generator to assume the load while the first generator is taken off line for maintenance or repairs. Potable water is contained in two 310 gallon pressurized holding tanks placed on either side of the habitat. Modifications made during the refurbishment are summarized in Table 1.
The transition from the MSB to the LSB was not just a shift in hardware support, but required revised operating protocols too. For example, the shore–based crew now monitors all buoy and habitat equipment that was previously accomplished offshore 24 hours a day on the MSB. Decompression at the end of missions is controlled within the habitat, where before it was conducted from the MSB by surface staff. During excursions, one technician remains in the habitat to monitor life support equipment and communications.
The second technician is available to accompany scientists on excursions and assist in service support, as well as operations. Underwater fill stations are located at two way–stations in the work area to facilitate tank fills away from Aquarius. The fill stations replace the time consuming and labor intensive (in terms of surface–based support) tank changes previously used. Aquanauts can also rest, eat and drink, and discuss their work during the ten minute tank filling operation at the way–station. The way–stations also have hard wired communications to the habitat via a hailer.
The advanced electronics and semi–autonomous systems will allow aquanauts greater capabilities to maximize their saturation diving experience. The cooperative effort between NOAA (NURP funding and administration, and NDBC providing the 10 meter discus buoy for conversion to the LSB), UNCW (system design, operation, and administration), and Harbor Branch Oceanographic Institution (provided a home for Aquarius during refurbishment, engineering assistance, and substantial in–kind support), provided Aquarius with upgraded capabilities to significantly further coral reef and oceanographic research in the Florida Keys National Marine Sanctuary, and to advance the evolution of living and working in the sea using the world’s only saturation laboratory for scientists.
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