Titanic tourist submersible live updates: Rescuers race against time as passengers are identified

The desperate search for a missing submersible that vanished during a mission to explore the wreck of the Titanic continued on Tuesday as more information about those onboard came to light.

The submersible, which is part of an OceanGate Expeditions tour that offers passengers a once-in-a-lifetime experience to explore the Titanic wreckage, went missing on Sunday after losing contact with the research vessel Polar Prince.

British billionaire and owner of Action Aviation Hamish Harding was among the five people onboard the vessel, along with prominent Pakistani businessman, Shahzada Dawood, and his son, Suleman. The other two people onboard have yet to be identified.

In the desperate search for the missing vessel touring the shipwreck of the Titanic deep in the Atlantic, crews are thinking of the lives of the five people on board first and foremost.

“The thoughts of the crew members and their families really drive our crews forward and all of the partners that have been working this complex case to make sure we can continue to find them,” Coast Guard Rear Admiral John Mauger said Tuesday morning on NBC's "TODAY" show.

Factors such as oxygen levels, intense water pressure, and the remoteness of the area make the search difficult.