He would later work as a junior research fellow at the California Institute of Technology and then as an astrophysicist at NASA's Goddard Space Flight Center from the 1970s until his death. Michalitsianos was involved with such projects as the Hubble Space Telescope and was the Deputy Project Manager of the Observatory Branch for Goddard's highly successful International Ultraviolet Explorer, in which he won several awards for his contributions.
After working as a junior research fellow at the California Institute of Technology, Michalitsianos became an astrophysicist at NASA's Goddard Space Flight Center in the 1970s and continued there until his death. He was involved with projects like the Hubble Space Telescope and served as the Deputy Project Manager for the International Ultraviolet Explorer, which he received awards for.