Question: Which cosmonaut, Franz Viehböck and Sigmund Jähn, visited the Mir space station in 1991 aboard Soyuz TM-13?
Sentence (from "Klaus-Dietrich Flade"): Klaus-Dietrich Flade (born August 23, 1952) is a German pilot and former German Aerospace Center astronaut who visited the Mir space station in 1992 aboard the Soyuz TM-14 mission, returning to Earth a week later aboard Soyuz TM-13.
Relevant evidence: No