Ch. 4— Technologies for Exploring the Exclusive Economic Zone • 145 



A third type of nuclear technique, neutron acti- 

 vation analysis, has been used with some success 

 to evaluate the components of manganese nodules 

 from the deep seafloor.'* The technique consists of 

 irradiating a sample with neutrons, using califor- 

 nium-252 as a source. Gamma rays that are emitted 

 as a result of neutron interactions then can be ana- 

 lyzed. Ideally, the identification and quantification 

 of elements can be inferred from the spectral in- 

 tensities of gamma ray energies that are emitted 

 by naturally occurring and neutron-activated radi- 

 oisotopes.'^ Although the neutron activation tech- 

 nique can be used at sea to obtain chemical analy- 

 ses of many substances, its use is limited by the 

 difficulty of taking precise analytical weights at sea. 

 The X-ray fluorescence method has proven both 

 easier to use at sea and less expensive. 



Manned Submersibles and Remotely 

 Operated Vehicles 



Both manned and remotely operated vehicles 

 (ROVs) have been working in the EEZ for many 

 years. One characteristic that all undersea vehicles 



"Ibid. 



'^A Borehole Probe for In Situ Neutron Activation Analysis, Open 

 File Report 132-85 (Washington, DC: U.S. Bureau of Mines, June 

 1984), p. 8. 



share is the ability to provide the explorer with a 

 direct visual or optical view of objects in real-time. 

 Another common characteristic is that undersea ve- 

 hicles operate at very slow speeds relative to surface- 

 oriented techniques. Indeed, a great deal of the 

 work for which undersea vehicles are designed is 

 accomplished while remaining stationary to exam- 

 ine or sample an object with the vehicle's manipu- 

 lators. As a consequence, neither manned nor un- 

 manned vehicles are cost-effective if they are 

 employed in large area exploration. Their best ap- 

 plication is in performing very detailed exploration 

 of small areas or in investigating specific charac- 

 teristics of an area. 



All manned submersibles carry a crew of at least 

 1 and as many as 12, one of which is a pilot. Most 

 of the many types of manned submersibles are 

 battery-powered and free-swimming; others are 

 tethered to a surface support craft from which they 

 receive power and/or life support (tables 4-5 and 

 4-6). A typical untethered, battery-powered 

 manned submersible is Alvin which carries a crew 

 of three (one pilot; two observers); its maximum 

 operating depth is 4,000 meters (13,000 feet). 



ROVs are unmanned vehicle systems operated 

 from a remote station, generally on the sea surface. 

 There are five main categories of ROVs: 



Table 4-5.— U.S. Non-Government Submersibles (Manned) 



Date Operating Power Crew/ Manipulators/ 



Vehicle built Length (ft) depth (ft) supply observers viewports Operators 



Arms 1,11,111 and IV 1976-1978 8.5 3,000 Battery 1/1 3/Bow dome Oceaneering International, Santa Barbara, CA 



Augusts Piccard 1978 93.5 2,000 Battery 6/3 0/1 Chicago, Inc., Barrington, IL 



Beaver.. 1968 24.0 2,700 Battery 1/4 1 /Bow dome International Underwater Contractors, City 



Island, NY, NY 



Deep Quest 1967 39.9 8,000 Battery 2/2 2/2 Lockheed l\/lissiles & Space, San Diego, CA 



Delta 1982 15.0 1,000 Battery 1/1 1/19 Marfab, Torrence, CA 



Diaphus 1974 19.8 1,200 Battery 1/1 1/Bcwdome Texas A & M University, College Station, TX 



Jim (14 ea) 1974 — 1,500 Human 1/0 2/1 Oceaneering International, Houston, TX 



Johnson-Sea-Link l&ll. . .^B7■\ 22.8 3,000 Battery 1/3 1/Panoramic Harbor Branch Foundation, Ft. Pierce, FL 



1975 



Mermaid II 1972 17.9 1,000 Battery 1/1 1/Bowdome International Underwater Contractors, City 



Island, NY 



Nekon B&C 1968 15.0 1,000 Battery 1/1 1 /Bow dome Oceanworks, Long Beach, CA 



1970 



1972 



Pioneer 1978 17.0 1,200 Battery 1/2 2/3 Martech International, Houston, TX 



Pisces VI 1976 20.0 6,600 Battery 1/2 2/3 International Underwater Contractors. City 



Island, NY 



Snooper 1969 14.5 1,000 Battery 1/1 1/10 Undersea Graphics, Inc., Torrance, CA 



Makalii 1966 17.7 1,200 Battery 1/1 1/6 University of Hawaii, Honolulu, HI 



Wasp 1977 - 2,000 Surface 1/10 2/Bow dome Oceaneering International, Houston, TX 



SOURCE: Busby Associates, Inc., Arlington, VA. 



