Question: Which cosmonaut, Franz Viehböck and Sigmund Jähn, visited the Mir space station in 1991 aboard Soyuz TM-13?
Context: Sigmund Werner Paul Jähn (born 13 February 1937) is a German cosmonaut and pilot, who in 1978 became the first East German (and German native) to fly in space as part of the Soviet Union's Interkosmos programme. Oleg Dmitriyevich Kononenko (Russian: Олег Дмитриевич Кононенко ) is a Russian cosmonaut.  He has flown to the International Space Station three times, as a flight engineer for Expedition 17 aboard Soyuz TMA-12, as a flight engineer on Expedition 30 and commander of Expedition 31 aboard Soyuz TMA-03M, and as a flight engineer on Expedition 44 and Expedition 45 aboard Soyuz TMA-17M.  Kononenko has accumulated over 533 days in orbit during three long duration flights to ISS. Mir EP-2 was a visiting expedition to the Mir space station conducted in June 1988 by cosmonauts Anatoly Solovyev, Viktor Savinykh and Aleksandr Aleksandrov.  Launched aboard the Soyuz TM-5 spacecraft, the crew spent ten days in space before returning to Earth aboard Soyuz TM-4.  The mission occurred while the EO-3 crew were aboard Mir. Soyuz TM-29 was a Russian manned spacecraft launched from the Baikonur Cosmodrome aboard a Soyuz 11A511U rocket.  It docked with Mir on February 22 at 05:36 GMT with Cosmonauts Viktor Afanasyev of Russia, Jean-Pierre Haigneré of France, and Ivan Bella of Slovakia aboard.  Since two crew seats had been sold (to Slovakia and France), Afanasyev was the only Russian cosmonaut aboard.  This meant that Russian engineer Avdeyev already aboard Mir would have to accept a double-length assignment.  After the February 27 departure of EO-26 crew commander Padalka and cosmonaut Bella aboard Soyuz TM-28, the new EO-27 Mir crew consisted of Afanasyev as Commander, Avdeyev as Engineer and French cosmonaut Haigneré. Soyuz TM-30 (Russian: Союз ТМ-30 , "Union TM-30"), also known as Mir EO-28, was a Soyuz mission, the 39th and final human spaceflight to the Mir space station.  The crew of the mission was sent by MirCorp, a privately funded company, to reactivate and repair the station.  The crew also resupplied the station and boosted the station to an orbit with a low point (perigee) of 360 and a high point (apogee) of 378 kilometers (223 and 235 miles, respectively).  The boost in the station's orbit, which was done by utilizing the engines of the Progress M1-1 and M1-2 spacecraft, made transit between Mir and the International Space Station impossible, as desired by NASA.  The mission was the first privately funded mission to a space station. 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. Franz Artur Viehböck (born August 24, 1960 in Vienna) is an Austrian electrical engineer, and was Austria's first cosmonaut.  He was titulated "„Austronaut“" by his country's media.  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. Soyuz TM-5 was the fifth cosmonaut-carrying spacecraft to visit the Russian Space Station Mir.  It was launched on June 7, 1988, carrying the Mir EP-2 mission's three-person crew.  This week-long stay on Mir occurred during the third long-duration Mir expedition, Mir EO-3.  The crew of EP-2 returned to Earth aboard Soyuz TM-4, while the TM-5 spacecraft remained docked to Mir, acting as the lifeboat for the long-duration crew.  On September 7, 1988, the TM-5 spacecraft undocked from Mir, and landed Mir EP-3 mission's two-person visiting crew.  The de-orbit procedures for Soyuz were revised after this flight, as multiple issues almost prevented the descent module's safe de-orbit and landing. Mir EO-8 (Russian: Мир ЭО-19 ) was the eighth manned expedition to the space station Mir, lasting from December 1990 to May 1991.  The crew, consisting of Russian cosmonauts Viktor Afanasyev and Musa Manarov, launched along with space journalist Toyohiro Akiyama on December 2, 1990 aboard Soyuz TM-11.  Akiyama returned aboard Soyuz TM-10 with the outgoing Mir EO-7 crew on December 10.  Afanasyev and Manarov returned aboard Soyuz TM-11 on May 26, 1991. Yury Viktorovich Romanenko (Russian: Ю́рий Ви́кторович Романе́нко , "Jurij Viktorovič Romanenko"; born August 1, 1944) is a former Soviet cosmonaut, twice Hero of the Soviet Union (March 16, 1978 and September 26, 1980).  Over his career, Yury Romanenko spent a total of 430 days 20 hours 21 minutes 30 seconds in space and 18 hours in space walks.  In 1987 he was a resident of the Mir space station, launching on Soyuz TM-2 and landing aboard Soyuz TM-3.  He remained on Mir for 326 days that was the longest stay in space at that time.  His son, Roman Romanenko is also a cosmonaut, and has become the third second-generation space traveler on Soyuz TMA-15 in May 2009.
Answer: Franz Artur Viehböck