[6] From 1942–51, Harmon worked first in the United States Naval Research Laboratory's Aircraft and Electrical Division, then in the Heat and Power and Ordnance Divisions at the National Bureau of Standards in Washington, D.C. During World War II at the Naval Research Laboratory and later in the Heat and Power Division, she worked on engineering problems such as temperature range in aircraft electrical equipment, high altitude carbon brush performance in aircraft motors and generators and the action of lubricants in high-speed bearings.
She also designed, placed into operation, and tested equipment for the industrial production of printed circuits for military applications.
[7][8] One of Harmon's major contributions to the field was the development of a hot die stamp method to create printed circuits in which silver conductors were infused on thermoplastics and thermosetting materials.
She liaised with the Manufacturing Department on Arma’s Inertial Guidance System for the Atlas ICBM and focused on microminiaturization in extraterrestrial vehicles and telemetry.
From 1962–1970, she was a senior engineer for Autonetics, a division of Rockwell International Corporation in Anaheim, California, where she was responsible for advanced technology for the fabrication of multilayer circuit boards for the Minuteman program.
She started Harmon Technical Consultants in 1970 and provided her expertise to numerous national and international corporations in the areas of printed circuits and multilayer board production problems.
[24][25] Her sister Ann Ferrari, participated in the Salk Polio Vaccine field trail, and served as Instructor of Physical Therapy at Stanford.