Search-and-rescue efforts are underway to find a missing vessel that takes tourists to see the Titanic shipwreck.
The vessel is called Titan and is owned by OceanGate Expeditions, which takes passengers to see the Titanic wreckage.
Titan can carry five people to a depth of 13,123 feet, according to the OceanGate website.
Notably, Titan is a submersible, not a submarine. As the National Oceanic and Atmospheric Administration website explains, a submarine can launch itself into the ocean from a port independently, while a submersible does not have the power to get to port, the bottom of the ocean, and back.
Instead, submersibles are launched from support ships, which take the submersible to the site where the vessel will deep dive, similarly to how a boat deposits a scuba diver into an area of the ocean to explore.
Titan's location is unknown because it lost contact with its support ship, Polar Prince, as CNN reported.
As OceanGate told the BBC, Titan's dive began on Sunday after Polar Prince escorted the submersible to the site of the Titanic wreckage, which is near Newfoundland, Canada. The submersible lost contact with Polar Prince less than two hours into its journey.
Five passengers were on board Titan for its dive, and the vessel is equipped with life support for those passengers for 96 hours from the time of departure, according to OceanGate's website.
The US Coast Guard is carrying out search-and-rescue operations to attempt to find the submersible, with Rear Admiral John Mauger of the US Coast Guard saying the "remote" location of the site is making the efforts more difficult.
"It is a remote area and it is a challenge to conduct a search in that remote area, but we are deploying all available assets to make sure that we can locate the craft and rescue the people on board," he said, according to The New York Times.
Ocean Gate released a media brief on Monday saying that it was "exploring and mobilizing all options to bring the crew back safely" and that the company's "entire focus is on the crewmembers in the submersible and their families."
As Insider previously reported, tickets to board an OceanGate expedition to the Titanic wreckage cost $250,000 each.