Victor 6000: The French robot that is the 'main hope' of finding the missing Titanic sub

Hopes are fading for the survival of the crew of the Titan, a small submersible craft that went missing on Sunday as it dived to the bottom of the North Atlantic to the wreck of the ill-fated Titanic.

As the reported oxygen reserves onboard the Titan are expected to run out, a French French oceanographic vessel L'Atalante arrived over the wreck site on Thursday bearing what many believe is the 5-man crew's only hope of being rescued - an underwater robot called Victor 6000.

L'Atalante, a research vessel operated by the French Institute for Exploitation of the Sea (Ifremer), "is currently using its multibeam echosounder to obtain a finer map of the landscape and enable Victor 6000 to dive more efficiently".

"However, this sounder will not be used to locate the submarine", according to Ifremer. 

This task rests with Victor 6000.

The Titan, which is owned by OceanGate Expedition, has been missing since it dived on Sunday to the wreck at a depth of 3,810 metres (around 12,500 feet).

On board the 6.7-metre-long craft are OceanGate's CEO and founder Stockton Rush, British billionaire adventurer Hamish Harding, British-Pakistani businessman Shahzada Dawood and his son Suleman, and French explorer Paul-Henri Nargeolet.

Since it lost contact, it has a theoretical autonomy of 96 hours. 

As of Thursday, its oxygen reserves could soon be exhausted, it is believed. There is no way of knowing if they have already run out or not, that is if the craft didn't sustain a catastrophic implosion event.

The Victor 6000 underwater robot is the only device in the area capable of diving to the wreck. It is remotely operated from L'Atalante via a cable that gives it theoretically unlimited autonomy.

The unmanned vehicle is capable of diving to depths of