One pilot and four passengers remain deep in the Atlantic after a submersible carrying Titanic tourists went missing on Sunday. The vessel has enough oxygen to last 96 hours, and U.S. and Canadian ships are intensely searching for the craft both underwater and on the surface. U.S. Coast Guard Rear Admiral John Mauger announced that forces will be expanding the search field into deeper waters as time runs out.

Tickets aboard the submersible cost $250,000 per person. The passengers on board include French explorer Paul-Henri Nargeolet and British billionaire Hamish Harding. Pakistani businessman Shahzada Dawood and his son Suleman are also on board the craft, piloted by Stockton Rush. Rush is the founder and CEO of OceanGate, which operates the submersible. The U.S. Coast Guard explained that the submersible lost contact with its mother ship about 2 hours after it went below the surface. The craft activated a distress signal, but it is unclear whether this was done manually or by an automated system.

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