Simone was born on 19 January 1919 in Toulon, France. Her father Henri Melchior and both grandfathers Jules Melchior (paternal) and Jean Baehme (maternal) were admirals in the French Navy. Simone’s mother was Marguerite Melchior, affectionately called Guitte. She had two brothers: Maurice, and Simone’s twin, Michel.

In 1924, Henri Melchior, as a director with Air Liquide (France’s main producer of industrial gases), moved his family to Kobe, Japan. Simone learned Japanese at the age of five years.

Simone met her future husband, Jacques, at a cocktail party in 1937. He was a naval officer of 26 and she was 17. They were married at Saint-Louis-des-Invalides, in Paris, on 12 July 1937.

In 1942, Simone’s father provided financing and the manufacturing expertise of Emile Gagnan at Air Liquide to build Jacques Cousteau’s aqua-lung. Simone was indirectly to hold the key to this significant step in diving history. She was present in 1943 at the testing of the prototype for the aqua-lung, in the Marne River outside Paris. The new invention was employed to locate and remove enemy mines after World War II.

The Cousteau family’s underwater investigation and exploration led to the purchase of the minesweeper Calypso on 19 July 1950. Thomas Loel Guinness bought the ship and leased it to Jacques for a dollar a year. Simone sold her family jewels for the Calypso’s fuel, and her fur to buy a compass and gyroscope. The Calypso set off in 1952 on her maiden voyage, to the Red Sea. Simone was the only woman on board.

In 1963, Simone became the world’s first female aquanaut by living in Starfish House, an underwater habitat, for the final four days of the Conshelf II project.

Describing his wife, Jacques Cousteau said, “She was the happiest out of camera range, in the crow’s nest of Calypso, for example, scanning the sea for whales. Nothing would get by her.” He continued, “She lives to spend hour after hour in the wind and the sun, watching, thinking, trying to unravel the mystery of the sea.” Simone died in 1990 of cancer. She received a full military funeral, during which her ashes were scattered over the Sea of Monaco.