The missing tourist submersible with five people onboard including British billionaire Hamish Harding has been missing since yesterday afternoon, and may have become stuck in the wreckage of the Titanic that it was diving to admire. 

The sub, owned and operated by OceanGate Expeditions, was taking a crew of five people including company CEO Stockton Rush, French explorer PH Nargeolet and Harding 12,500ft underwater as part of its $250,000-a-head Titanic tour. 

The crew launched at around 4am yesterday but lost communication with the mothership a short while afterwards. According to OceanGate's website, the sub can last for up to 96 hours underwater with five people consuming oxygen.