What does the East German Cosmonaut Sigmund Jahn now do for a living?
Mongolia

Dear mongolia,

Since 1993, Sigmund Jähn works as a consultant for the German Research
Centre for Aeronautics and Astronautics (DLR = Deutsches Zentrum für
Luft- und Raumfahrt), and as a representative for the European Space
Agency (ESA), in the "Star City" astronaut training center of Korolev,
near Moscow. With his extensive practical experience and theoretical
knowledge concerning space travel, he accompanies the European
astronauts during their training in the Russian facilities and
prepares them for their missions.


Sources:

Raumfahrer.net: Sigmund Jähn, der erste Deutsche im All
http://www.raumfahrer.net/news/raumfahrt/25082003211502.shtml

ZDF Heute Magazin: Sigmund Jähn
http://www.heute.t-online.de/ZDFheute/artikel/11/0,1367,MAG-0-2062667,00.html

Sternwarte Drebach: Sigmund Jähn
http://www.sternwarte-drebach.de/p17737.htm

Vogtländer.de: Sigmund Jähn - Der erste Deutsche im Weltall
http://www.vogtlaender.de/interessantes/jaehn.shtml

Search terms used:
"Sigmund Jähn" heute
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"Sigmund Jähn" heute esa dlr
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"sigmund jähn" heute sternenstädtchen
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"star city" korolev
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=%22star+city%22+korolev&meta=

Hope this answers your question!
Best regards,
Scriptor