DelCorso served in the Women’s Army Auxiliary Corps (WAAC) from February 1943 to October 1943. She served as a secretary to the adjutant, Capt. LaCaze. While at Fort Devens, Mass., she interviewed for a special assignment by officers from the Manhattan Project, researching the development of the atom bomb. She was accepted and with 10 other women, sent to New York where they were stationed on the 12th floor of the Collingwood Hotel on Herald Square.
The Manhattan Project Headquarters was located on Fifth Avenue, where DelCorso and others served. She was assigned to serve as a TWX operator in a code room with other women. Their duties were sending and receiving coded messages to and from various sites that were researching the development of the bomb. DelCorso said she and her comrades did not know what the project was until the bomb was dropped on Hiroshima. DelCorso’s service to her country was cut short, due to a perforated ear drum. She regrets not being able to serve longer, but she said her brief service was interesting and rewarding. She received a Honorable Service Lapel Button for her duties.