The Advanced SEAL Delivery System (ASDS) was a midget submarine operated by the United States Navy and United States Special Operations Command. It provided stealthy submerged transportation for United States Navy SEALs from the decks of nuclear submarines for use as an insertion platform for covert and clandestine special operations missions. The ASDS was canceled in 2009 due to cost overruns and reliability issues, after the prototype was destroyed in a fire in 2008. , the Navy plans to replace the ASDS with the Dry Combat Submersible, a similar midget submarine being developed by Lockheed Martin. Mission ASDS was conceived to address the need for stealthy long-range insertion of special operations forces on covert or clandestine missions. It was designed to replace the wet SEAL Delivery Vehicle (SDV), which exposed combat swimmers to long, cold waits during transit that impeded combat readiness on arrival, limited operational range, and hindered underwater navigational capability. The primary limitation on the SDV's range is not fuel or batteries but water temperature, as Navy SEALs can only stay in cold water for so long, even with wetsuits. Development The first study to define the ASDS was performed in 1983. Competitive conceptual designs were developed in the late 1980s, the Request for proposal was issued in 1993, and the first contract for design and construction of the ASDS was awarded in 1994. The Navy stated a requirement for six boats, but that was established before it decided to convert four s to guided-missile submarines (SSGNs) with the additional mission of support of special operations forces. Each SSGN is capable of carrying two ASDS vehicles. Detailed design of the first ASDS was started in 1994, and hull construction began in 1996, at a cost of $160 million, to a low bid for the delivery of $69 million for the first ASDS (to include non-recurring design costs, fabrication, and testing), and subsequent copies for $25 million each. It was delivered for testing and evaluation in 2000 and cost $300 million, including vendor and program office costs. Subsequent submarines were estimated to cost $125 million each, based on a 2001 estimate. Five more were planned. The first ASDS became operational (completed testing and evaluation) at Naval Station Pearl Harbor, Hawaii, in 2003, six years behind schedule. From there, it was deployed to the Indian Ocean and Persian Gulf on board Los Angeles-class nuclear attack submarine , as a unit