Who are the passengers on board the Titanic submersible? AFP

British billionaire Hamish Harding, Pakistani tycoon Shahzada Dawood and Dawood's son Suleman, French submarine operator Paul-Henri Nargeolet, and OceanGate Expeditions CEO Stockton Rush are on board a missing submersible near the wreck of the Titanic which is at the heart of a rescue mission by the US Coast Guard.