FILE - In this photo provided by U.S. Navy, the Los Angeles-class fast attack submarine USS Oklahoma City (SSN 723) returns to U.S. Naval Base in Guam, Aug. 19, 2021. The vessel that went missing Sunday, June 18, 2023, in the North Atlantic while exploring the Titanic is not a submarine, it's a submersible. The National Oceanic and Atmospheric Administration says a submarine has enough power to leave port and come back to port under its own power while a submersible is not autonomous. (Mass Communication Specialist 3rd Class Naomi Johnson/U.S. Navy via AP, File)FILE - In this Dec. 15, 2016, photo provided by the U.S. Navy, the Seawolf-class fast-attack submarine USS Connecticut (SSN 22) departs Puget Sound Naval Shipyard in Bremerton, Wash., for sea trials following a maintenance availability. The vessel that went missing Sunday, June 18, 2023, in the North Atlantic while exploring the Titanic is not a submarine, it's a submersible. The National Oceanic and Atmospheric Administration says a submarine has enough power to leave port and come back to port under its own power while a submersible is not autonomous. (Thiep Van Nguyen II/U.S. Navy via AP, File)In this photo released by Action Aviation, the submersible Titan is prepared for a dive into a remote area of the Atlantic Ocean on an expedition to the Titanic on Sunday, June 18, 2023. Rescuers raced against time Tuesday, June 20, to find the missing submersible carrying five people, who were reported overdue Sunday night. (Action Aviation via AP)
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FILE - In this photo provided by U.S. Navy, the Los Angeles-class fast attack submarine USS Oklahoma City (SSN 723) returns to U.S. Naval Base in Guam, Aug. 19, 2021. The vessel that went missing Sunday, June 18, 2023, in the North Atlantic while exploring the Titanic is not a submarine, it's a submersible. The National Oceanic and Atmospheric Administration says a submarine has enough power to leave port and come back to port under its own power while a submersible is not autonomous. (Mass Communication Specialist 3rd Class Naomi Johnson/U.S. Navy via AP, File)
The vessel that went missing Sunday in the North Atlantic while exploring the Titanic's wreckage is a submersible not a submarine, and there is a key difference.
The Titan, with five people on board, remained missing Tuesday even as an international search and rescue effort was underway.
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The National Oceanic and Atmospheric Administration explains the difference. A submarine has enough power to leave port and come back to port under its own power.
But a submersible has more limited power and range. It needs a mother ship from which to launch, to return to, and for support and communications.
The Titan's mother ship is the Polar Prince, a former Canadian Coast Guard icebreaker.
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