Tanner flew aboard the Space Shuttle "Atlantis" on the STS-66, November 3–14, 1994, performing the Atmospheric Laboratory for Applications and Science-3 (ATLAS-3) mission. ATLAS-3 was the third in a series of flights to study the Earth's atmosphere composition and solar effects at several points during the Sun's 11-year cycle. The mission also carried the CRISTA-SPAS satellite that was deployed to study the chemical composition of the middle atmosphere and retrieved later in the mission. Tanner logged 262 hours and 34 minutes in space and 175 orbits of the Earth.