Search and rescue officials say the men likely died on Sunday – before military planes using sonar buoys detected what they thought could have been SOS ‘banging’ sounds in the water.

The victims are OceanGate CEO Stockton Rush, French Navy veteran Paul-Henri (PH) Nargeolet, British billionaire Hamish Harding, Pakistani businessman Shahzada Dawood, and his son Suleman, who was just 19.

‘The implosion would have generated a significant, broadband sound that the sonar buoys would have picked up,’ explained Rear Admiral John Mauger of the US Coast Guard at a press conference today.

In a heartbreaking tribute, Richard Garriott, president of the Explorers Club, of which Harding and Nargeolet were both members, said that the men had been drawn to explore ‘in the name of meaningful science for the betterment of mankind.’

‘Our hearts are broken. I am so sorry to have to share this tragic news,’ Garriott announced. He said the club was ‘grateful for all our members and the scientific and exploration community around the world who have mobilized personnel and resources to support the search and rescue’.

Garriott described Harding as a ‘dear friend’ to himself and the club. ‘He holds several world records and has continued to push dragons off maps both in person and through supporting expeditions and worthy causes,’ he wrote.

‘We’re heartbroken for the families, friends and colleagues of those who were lost. Their memories will be a blessing and will continue to inspire us in the name of science and exploration,’ Garriott said.