A two-week inquiry by the US Coast Guard is looking into the causes of the tragic implosion that killed all five people onboard the Titan submersible.

Here are five takeaways from the first of the two-week set of hearings: Investigators with the US Coast Guard revealed one of the crew's final messages before it lost contact with a ship above water: "All good here.

The US Coast Guard has heard a week's worth of testimony from people close to the Titan submersible that imploded last June, killing all five aboard. Investigators are seeking to uncover the details of what led to the tragedy and find recommendations that could prevent future deadly voyages.