To gain assurance that the designs of the submarine and its subsystems will result in the submarine successfully performing its various missions, the Navy requires that the Program Manager use computer simulations as a principal tool to model the NSSN’s capabilities against existing and potential threats. A More Capable Threat Has Been Defined

In April 1996, the Office of Naval Intelligence revised its classified underseas threat assessment and noted several technological advances in the open-ocean, antisubmarine warfare threat. Several improvements resulting in a more capable threat were noted over the previous threat of record, which the Navy used to model the survivability of the NSSN design in the 1995 assessment. As a result of the 1995 assessment, the Navy tester expressed concern that if the NSSN were just to meet minimum requirements for survivability, the NSSN may not be operationally effective against the most capable threat that the Navy was projecting at that time. The Navy tester’s report noted reduced performance of several subsystems and developmental problems in others that also will result in reductions in planned performance. The Navy tester concluded that the NSSN could potentially be operationally effective and suitable. However, he recommended that a new NSSN modeling baseline be established to reflect more current information, because the performance of some subsystems had been reduced below the performance modeled in the 1995 NSSN milestone II cost and operational effectiveness analysis and the April 1995 early operational assessment. The tester also recommended that this new design baseline be evaluated against the currently projected threat. Navy program officials are cognizant of the Navy tester’s report but have indicated that there are no plans to perform an updated survivability modeling of the total system against the new threat. Without an evaluation that reflects current conditions, DOD and Navy program officials appear to have little basis for their confidence in how the submarine, with its design changes, will perform. Available research and development funding could be used for this modeling.
Why GAO Did This Study

GAO reviewed: (1) the status of the new attack submarine (NSSN) development program; (2) current information on the antisubmarine warfare threat; and (3) the Navy's plans to model the NSSN's survivability.

What GAO Found

GAO noted that: (1) since modeling the NSSN's survivability in 1995, the Navy, because of technical and funding limitations, has modified the design for some subsystems that reduce performance below the optimal levels used to model the 1995 baseline design; (2) other systems also have developmental problems; (3) at the same time, Navy threat assessments have reported that the open ocean antisubmarine warfare threat has improved, resulting in a more capable threat than previously projected; (4) the Navy tester's 1997 assessment report concluded that the NSSN could potentially be operationally effective and suitable, but noted a number of significant changes and risks in the development program; (5) the report also noted several technological advances in the open ocean antisubmarine warfare threat; (5) in addition, the report stated that budgetary pressures resulted in tradeoffs in some of the performance modeled in the NSSN milestone II cost and operational effectiveness analysis and the tester's 1995 early operational assessment; (6) as of November 1997, the Navy program manager planned no additional survivability modeling to test the NSSN with its potential for reduced performance against the improved threat; (7) however, as a result of its 1997 assessment, the Navy tester recommended that the Navy develop a new modeling baseline that reflects the reduced performance of some subsystems and that this new design baseline be evaluated against the increased threat; and (8) without such modeling, the Department of Defense and Navy program officials appear to have little basis for their confidence that the currently designed submarine will perform as expected.