At the age of 26 years - is already having a doctoral degree, academic rank, and recognition in Europe - Pallas was invited by the Russian empress Catherine II to work as an adjunct Petersburg Academy of Sciences and the College of assessors. After some hesitation, July 30, 1767 Pallas arrived in St. Petersburg with his family - his young wife and small daughter. Under the decree of the empress, he was immediately sent to the ambitious expedition across Russia, which wanted to Lomonosov himself, in order to explore the geological, mineralogical, animal and plant resources of the country, as well as to identify the historical, socio-economic and ethnographic peculiarities of individual regions. From the Academy, he was on a salary of 800 rubles a year, which in those times was a very decent salary.

   Catherine II actively interested in the device and the wealth of its empire, and the idea of a comprehensive study arose after the completion of her own journey down the Volga from Tver to Simbirsk in 1767. Soon she began the order of new expeditions - several "astronomical" and "natural" groups. The task consisted of six astronomical units calculate the solar parallax at passage of Venus across the disk of Sun, in July 1769 (thus given the opportunity to define more precisely the distance between Earth and the Sun).

   In general, scientific expeditions Katherine period covered vast territory of Russia - from the Barents Sea in the north and to the Black Sea (the North Caucasus and the Crimea) and the Caspian Sea (up to the border with Persia) seas to the south and from the Baltic Sea (Riga) in the west to the Trans-Baikal (to the borders with China) to the east.

   Route squad Pallas was the first year the cities of St. Petersburg - Great Novgorod - Tver - Klin - Moscow - Vladimir - Kasimov - Moore - Arzamas - Penza - Simbirsk - Samara - Stavropol (now Togliatti) - Simbirsk. 2 Oct, 1768 expedition arrived in Ufa, where remained until 1770. In subsequent years, the route passed through towns and villages of Lower Volga region, Urals, Siberia: Chelyabinsk, Yekaterinburg, Verkhoturov, Tyumen, Tobolsk, Omsk, Semipalatinsk, Barnaul, Tomsk, Achinsk, Irkutsk, Krasnoyarsk, Sarapul, Buzuluk, Uralsk, Tsaricino Tambov and Moscow. In 1774 Pallas returned to St. Petersburg.

   By its scale and complexity, such an expeditionary project and now look to difficult. The long journey was very difficult and require enormous tension forces. First of all, Pallas was faced with unusual it has a continental climate. Had to sleep in the abandoned winter hut, and in the dugouts, and even outdoors. A lot of trouble delivering the road, it was difficult to get good horses. In winter, sleigh riding in the summer - on the carts, sailed on the boat. Others are troubled areas, where nomads, has recently entered into Russia, not Tchuraev of looting and robbery.

   In total, the route pallasovskogo squad was 27 264 versts (about 29 085 km), of which 6000 miles (about 6400 km) did VF Zuev, and NP Sokolov. Overtake the huge unexplored space of Russia and Eurasia, following the truly titanic scientific work, Pallas from satellites back to St. Petersburg. In the age of 33 he was already sedym and the sick person.