A rescue operation has begun for a submarine exploring the Titanic

(CNN) — The U.S. Coast Guard began a search and rescue operation Monday for a submarine that went missing during its voyage toward the remains of the Titanic. CTV NewsA CNN affiliate.

Oceangate Expeditions, the group behind the trip, said it was “exploring and mobilizing all options to bring the crew safely.”

“Our entire focus is on the crew of the submarines and their families. We are very grateful for the extensive assistance we have received from various government agencies and deep sea agencies in our efforts to re-establish contact with the submarine,” the team said. “We are working to ensure the safe return of crew members.”

The submersible can seat five people, the company said on its website. It is unclear how many people were on board.

CNN contacted the Boston Coast Guard and officials in Newfoundland, Canada.

He Titanic It struck an iceberg on its maiden voyage and sank in the North Atlantic in April 1912, killing more than 1,500 people. Discovered in 1985, the wreck of the Titanic lies in two parts on the ocean floor, nearly 13,000 feet below southeast Newfoundland.

In recent times, tourists are offered expensive private tours that allow them to see the wreck up close.

An archived version of the OceanGate website is available The Internet Archive’s Wayback MachineExplains what travelers can expect on a $250,000 trip.

“Follow in the footsteps of Jacques Cousteau and become an underwater explorer aboard the RMS Titanic. This is your chance to step out of the ordinary and discover something truly extraordinary,” the website says. “Be one of the few to see the Titanic with your own eyes.”

The eight-day voyage departs from St. John’s, Newfoundland and begins with a 400-nautical-mile voyage to the wreck site.

There, up to five people, including a pilot, a “content specialist” and three paying passengers, board a submarine called a “Titan” and descend to the bottom of the ocean.

“As soon as the submarine leaves, as you go deeper into the ocean, you start seeing aliens whining past your viewfinder. It takes two hours to get off, but it seems like a blink of an eye,” it explains. Website.

According to OceanGate, Titan is a 23,000 pounds submersible Made of carbon fiber and titanium. As a safety measure, the company says the sub uses a “proprietary real-time hull health monitoring (RTM) system” that analyzes the pressure and structural integrity of the vessel. Life support is available for a crew of five for 96 hours, the website said.

— CNN’s Tanika Gray contributed to this report.