From November 1994 to March 1995, Sega was the NASA Director of Operations, Star City, Russia (The Gagarin Cosmonaut Training Center) responsible for managing NASA activities at Star City. These activities involved building an organization and infrastructure to support astronaut and cosmonaut mission and science training for flight on the Russian Space Station Mir. He also participated in training on Russian Space Systems and was the first American to train in the Russian EVA suit (Orlan) in their underwater facility (Hydrolaboratory). A veteran of two space flights (STS-60 in 1994 and STS-76 in 1996), Sega logged over 420 hours in space.
STS-60 was the first joint United States/Russian Space Shuttle mission. Launched on February 3, 1994, STS-60 was the second flight of the Space Habitation Module-2 (Spacehab-2), and the first flight of the Wake Shield Facility (WSF-1). During the 8-day flight, the crew of Discovery conducted a wide variety of biological, materials science, earth observation, and life science experiments. Sega was the flight engineer for ascent and entry on this mission, performed several experiments on orbit, and operated the robotic arm, berthing the Wake Shield onto its payload bay carrier on four separate occasions. Following 130 orbits of the Earth in 3,439,705 miles, STS-60 landed at Kennedy Space Center, Florida, on February 11, 1994. With the completion of his first space flight, Sega logged 8 days, 7 hours, 9 minutes in space.