of Expeditionary Strike Group One. The first ASDS was never joined by other units, as the program was derailed by escalating costs and technical problems. A Congressional Budget Office (CBO) in 2003 cited two major technical problems: noisy propellers and silver-zinc batteries that depleted more quickly than planned. A new propeller made of composite material was developed to rectify the noise problem. Development is under way on lithium-ion batteries to replace the silver-zinc batteries and enable the electrical system to meet the Navy's requirements. Yardney Technical Products of Pawcatuck, Connecticut, was awarded a $44 million contract modification to provide four lithium-ion batteries for the ASDS program by May 2009. In the end, cost, technical, and reliability issues proved insurmountable, and the ASDS was cancelled in 2009. Cost overruns According to the Government Accountability Office (GAO), the initial $70 million cost-plus contract ended up costing the government $885 million by 2007. Instead of entering service in 2000, as was initially planned, testing continued and the first boat was not delivered until July 2003. Global Security adds that the program was initially projected to cost $527 million over its lifetime, including delivery of all six subs, but by 2003 total program cost was predicted to rise to more than $2 billion—significantly more than the $1.4 billion SSGN Tactical Trident conversion program to which it is related. An independent GAO audit of the program published in 2007 placed the blame for the cost overruns on Northrop Grumman, the prime contractor, for failing to meet their time and cost estimates and on the Navy for accepting the ASDS "as is" and failing to hold Northrop Grumman accountable for cost overruns and delays. After 2000, most of the cost overruns were for cost- and incentives . The Department of Defense endorsed GAO's findings. Funding was provided via Congressional line item to the Special Operations Command. The Navy Deep Submergence Office was selected as the technical design agent and program office. Technical assistance was provided by the Navy Experimental Dive Unit, Panama City, Florida; the Naval Special Warfare Command, Coronado, California; SEAL Delivery Vehicle Team 2, Norfolk, Virginia; and the Special Operations Command (SOCOM) Special Operations and Acquisition Logistics (SOAL), Tampa. Critical design failures Power – The long range requirement strained the ability of existing battery technology. Shock – Shock requirements for the vessel and its equipment were four times the limit for contemporary nuclear submarines.