Which space station did Austrian Franz Viehböck and Germany's Klaus-Dietrich Flade both visit for a week in the early 1990s?
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. 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.
Mir