 In 1929 and 1930 icebreaker "Sedov" carried groups of scientists to Franz Josef Land and later to former Emperor Nicholas II Land, the last major piece of unsurveyed territory in the Soviet Arctic.In 1926 the Presidium of the Central Executive Committee of the USSR had renamed the still not fully explored land "Severnaya Zemlya" (Northern Land).This archipelago was completely mapped under Ushakov, together with geologist Nikolay Urvantsev, surveyor Sergei Zhuravlev and radio operator Vasily Khodov thoroughly surveyed Severnaya Zemlya during a 1930–1932 expedition to the archipelago.