The submarine known as the Titan has gone missing since long, four passengers including the operator are suspected to be dead after the find of a part of the submarine.
Theories are similar to that the controller of the submarine, Ran out of battery that made no control available of the sub.
The main station lost contact with the sub 45 minutes after going on the path to the Titanic wreck.
Later it was known that the people in the sub had a limited air.
You could ask your parents for more info.