Best and worst case scenarios to explain Titan’s loss of contact with surface

Titan’s hull is a carbon fibre structure that connects two titanium composite domes – other deep-sea vessels use steel or titanium alone. Photograph: OceanGate

For an expedition as hazardous as the Titan’s descent to the Titanic, there is a long list of onboard systems that need to be checked and a host of environmental hazards that must be identified and assessed before the voyage begins.

“When you are putting people in a potentially dangerous position like this you want to be absolutely sure everything’s checked through before getting under way,” said Stefan Williams, a professor of marine robotics at the University of Sydney. “We have an extensive checklist before we put anything in the water.”