One of the five people in a missing submersible craft that was exploring the Titanic wreckage is a record-setting daredevil who has flown to space and traversed the planets deepest underwater trenches, and who has acknowledged that being rescued is not always a possibility.

If something goes wrong, you are not coming back, British explorer and businessman Hamish Harding told the Indian newsmagazine The Week in 2021 after completing a record-setting dive in the Mariana Trench, the worlds deepest part of the ocean.

That four-hour dive explored the bottom of Challenger Deep, which has a depth of 35,860 feet. For comparison, the Titanic is nearly 13,000 feet below sea level.