Question: Which space station did Austrian Franz Viehböck and Germany's Klaus-Dietrich Flade both visit for a week in the early 1990s?
Sentence (from "Franz Viehböck"): He visited the Mir space station in 1991 aboard Soyuz TM-13, returning aboard Soyuz TM-12 after spending just over a week in space.
Relevant evidence: Yes