Question: Dumitru Prunariu and Ernst Messerschmid, have which occupation in common?
Context: The Convention of Balta Liman of 1 May 1849 was an agreement between the Russian Empire and the Ottomans regulating the political situation of the two Danubian Principalities (the basis of present-day Romania), signed during the aftermath of the Revolutions of 1848.  Moldavia, which had been placed under Russian occupation in late spring 1848 following a revolutionary attempt, and Wallachia, where a liberal Provisional Government had briefly assumed power before facing a common Ottoman-Russian reaction, were confirmed their previous status of Ottoman suzerainty and Russian protectorate (first established in 1831–32 by the "Regulamentul Organic").  Minor provisions were added, signifying a relative increase in Ottoman influence—namely, "hospodars" were no longer elected by the local National Assemblies for life, and instead appointed by the Sublime Porte for seven-year terms.  A common military presence was maintained until 1851.  The document led to the appointment of Barbu Dimitrie Ştirbei as hospodar of Wallachia and Grigore Alexandru Ghica as hospodar of Moldavia.  The Convention was rendered void by the Crimean War (during which the Principalities fell under Austrian occupation), and the statutory system itself was annulled by the 1856 Treaty of Paris. Pavel Ludikar (3 March 1882 – 19 February 1970) was a Czech operatic bass who had a highly successful international singing career from 1904 through 1944.  He began his career in his native country and by 1911 had arisen at many of the major opera houses in Europe.  From 1913 to 1935 his career was mainly centered in North and South America.  The peak of his opera career was reached at the Metropolitan Opera in New York City, where he was committed from 1926 to 1932.  He returned to Europe in 1935 to assume directorship of the Neues deutsches Theatre in Prague, remaining there until the theatre was closed in September 1938 due to Nazi occupation, effectively ending his stage career.  The height of his later years in Prague was his portrayal of the title hero in the world premiere of Ernst Krenek's "Karl V" in June 1938. N. D. Cocea (common rendition of Nicolae Dumitru Cocea, ] , also known as Niculae, Niculici or Nicu Cocea; November 29, 1880 – February 1, 1949) was a Romanian journalist, novelist, critic and left-wing political activist, known as a major but controversial figure in the field of political satire.  The founder of many newspapers and magazines, including "Viața Socială", "Rampa", "Facla" and "Chemarea", collaborating with writer friends such as Tudor Arghezi, Gala Galaction and Ion Vinea, he fostered and directed the development of early modernist literature in Romania.  Cocea later made his name as a republican and anticlerical agitator, was arrested as an instigator during the 1907 peasant revolt, and played a leading role in regrouping the scattered socialist clubs.  His allegiances however switched between parties: during World War I, he supported the Entente Powers and, as a personal witness of the October Revolution, the government of Soviet Russia, before returning home as a communist. Dumitru-Dorin Prunariu (] ; born 27 September 1952) is a Romanian cosmonaut.  He flew in space aboard Soyuz 40 spacecraft and Salyut 6 space laboratory.  He was in team with another Romanian cosmonaut called Dumitru Dediu. Mitică (] ) is a fictional character who appears in several sketch stories by Romanian writer Ion Luca Caragiale.  The character's name is a common hypocoristic form of "Dumitru" or "Dimitrie" (Romanian for "Demetrius").  He is one of the best-known figures in Caragiale's 1901 collection "Momente şi schiţe", as well as in Romanian humor at large.  Mitică is a male resident of Bucharest whose background and status are not always clear, generally seen as an allegory of the average Bucharester or through extension, inhabitants of Romania's southern regions—Wallachia and Muntenia.  According to accounts, he was based on a resident of Sinaia, whom Caragiale had befriended. Franz Ernst Christian Neumann (30 January 1834 – 6 March 1918) was a German pathologist who was a native of Königsberg.  His common name was Ernst Christian Neumann (without Franz at the beginning). The Ministries Trial (or, officially, the United States of America vs. Ernst von Weizsäcker, et al.) was the eleventh of the twelve trials for war crimes the U.S. authorities held in their occupation zone in Germany in Nuremberg after the end of World War II.  These twelve trials were all held before U.S. military courts, not before the International Military Tribunal, but took place in the same rooms at the Palace of Justice.  The twelve U.S. trials are collectively known as the "Subsequent Nuremberg Trials" or, more formally, as the "Trials of War Criminals before the Nuremberg Military Tribunals" (NMT). Prof. Dr. Ernst Willi Messerschmid (born May 21, 1945) is a German physicist and former astronaut. Mesne (pronounced "mean") profits are sums of money paid for the occupation of land to a person with right of immediate occupation, where no permission has been given for that occupation.  The concept is feudal in origin, and common in countries which rely on the English legal system (including many former British colonies).  The word is derived from the root word demesne. On May 14, 1981 Romania became the 11th country in the world to have an astronaut in space.  That astronaut, Dumitru Prunariu is today's president of Romanian Space Agency.
Answer: astronaut