Hedy Lamarr, the Movie Star who Invented a Torpedo Guidance System

Hedy Lamarr's name is known to millions of movie fans as one of the great beauties of Hollywood's Golden Age. She appeared in over 25 movies from 1933 to 1957, and starred with some legendary names such as Spencer Tracy and Clark Gable. She starred in such hit movies as 'White Cargo' and 'Tortilla Flat' in 1942 and she was Delilah to Victor Mature's Samson in 'Samson and Delilah' in 1949.

What is not so well known is that in 1942, at the very time she was being feted as one of the most beautiful and successful stars in Hollywood, Hedy was able to co-invent and patent a torpedo guidance system that was two decades ahead of its its time and whose basic principles lie behind anti-jamming devices used in today's communication satellites.

Hedy Lamarr was born Hedwig Eva Maria Kiesler in Vienna in November, 1914 into a conventional middle class family. As a young girl Hedwig decided she wanted to be an actress and when she left school she was accepted into Max Reinhardt's acting school in Berlin. In 1933 in her fifth film 'Extase' closeups of her face in supposed orgasm, and long shots of her in the nude, gave the film and Hedwig international notoriety.

Hedwig's career as an inventor started with her first husband whom she married in 1933. He was Friedrich Mandl, aged 32, a wealthy businessman and the chairman of a company which manufactured armaments including aircraft guidance systems. During the course of their 4 year marriage Hedwig Mandl became one of Vienna's foremost society hostesses, giving elaborate dinner parties for the cream of Europe's society including foreign politicians such as Hitler and Mussolini.

Hedwig obviously learned a lot from the dinner table conversations, which often were about her husband's increasing interest in control systems for military aircraft. When her marriage to Mandl ended amid much unpleasantness in 1937 (he was a possessive and jealous man who did not like her having an acting career) Hedwig fled to America, changed her name to Hedy Lamarr, and became an immensely successful and glamorous movie actress. But she never forgot the knowledge garnered around the dinner tables of Viennese society. It came in very useful when she met one of her neighbours in Hollywood, film composer and magazine writer, George Antheil.

George Antheil was an American, born in New Jersey in 1900 whose parents came originally from Prussia. He studied music in Philadelphia then travelled to Berlin and Paris as a concert pianist and avante-garde composer.

Whilst in Paris in 1924, he composed a 'Ballet Mécanique', scored for 16 'player' pianos (in other words, not played by human pianists) and which required the synchronisation of the output of each piano to each other and also to a back-projected movie. (The piece also needed four bass drums,  seven electric bells, a siren, three xylophones, a tam-tam,and three different-sized airplane propellors as well as two conventional human-played grand pianos.) It was never properly played at the time simply because the technology for linking and synchronizing multiple player pianos, although theoretically possible by using a hole punched piano roll, turned out not to be practical.

Antheil's reputation as a glandular specialist was such that Hedy Lamarr approached him in the summer of 1940 with an enquiry about whether she could have her breasts enlarged. When their conversation switched to music and to weapons they realised they could combine their knowledge to produce an innovative device.

What Lamarr and Antheil did was combine his knowledge of piano roll synchronisation with her knowledge of torpedo guidance systems to create one of the earliest known forms of the telecommunications method known as "frequency hopping", which used slotted paper rolls similar to player-piano rolls to co-ordinate changes in transmitter and receiver frequencies. It used eighty-eight frequencies, the same as the number of keys on a piano, and was intended to make radio-guided torpedoes harder, if not impossible, for enemies to detect or to jam.

After months spent working on their system Lamarr and Antheil sent a description of it to the National Inventors Council in December, 1940. The Council received many thousands of ideas of which very few passed detailed inspection but Antheil and Lamarr were encouraged to develop their idea further. This they did and were able to patent it on August 11, 1942, under the name 'Secret Communications System'.

The idea was years ahead of its time, and due to the state of mechanical technology in 1942 it was not a practical possibility and the patent expired before the inventors could profit from the new technology they had helped to create.

It was implemented in the USA in 1962, when it was used by the U.S. navy during the blockade of Cuba but this was after the patent had expired. The technique of frequency hopping is now widely used in modern technology including cellular phones.

Hedy Lamarr's Hollywood career faded during the 1950s and she retired from movie-making in 1958 at the age of forty-four. She married six times in all. She died in Florida in January 2000, aged 85. The first Inventor's Day in Germany was held on 9 November 2005, to honor her work on what would have been her 92nd birthday.

In 2003, a series of advertisements were run to attract recruits to the Boeing Corporation. They prominentlly featured the beautiful Hedy Lamarr but only as a woman of science. No reference to her film career was made.