Zinaida Yershova  Zinaida Vasilyevna Yershova (; 23 October 1904 — 25 April 1995) was a Russian chemist, physicist and engineer. She spent her entire career working with radioactive elements and headed laboratories producing radioactive materials used mostly in the Soviet atomic bomb project and the Soviet space programme. She was born in Moscow. After leaving school in 1923, she enrolled at Moscow State University in the faculty of Physics and Mathematics. She joined a radiochemical laboratory. In 1924, Vitaly Khlopin, deputy director of the recently started Radium Institute in Petrograd posted an advertisement aimed at university students in Moscow. From then, Ershova was under the supervision of and cooperated with Khlopin. Noticing her potential, he advised her to work at the Moscow Plant of Rare Elements, where radium was first produced in the Soviet Union industrially. She graduated from university in 1929. In 1930, she began work as a specialist processing radium from the Tyuya-Muyun deposits (in Kyrgyzstan) and quickly became head of the physical laboratory. The first batches of radium produced by the young team were released in the winter of 1931, 200 milligrammes, 90% pure. In 1936, she was sent for an internship to the Marie Curie laboratory in Paris. Under Irene Joliot-Curie, she published a paper in 1937 in "Journal de Physique": 'Estimation of the ratio uranium-238/uranium-235 in U-Y'. On the recommendation of Khlopin, she was sent to work at (State Institute of Rare Metals) and was appointed head of the radium laboratory. When the Nazis invaded the Soviet Union in 1941, she was evacuated to Kazakhstan with her family. In 1943, she was called back to Moscow urgently by the government. Physicist Igor Kurchatov, one of the leaders of the Soviet atomic project, asked her to produce uranium carbide and uranium metal; this was done at Giredmet and used for nuclear physics research and for the construction of the first European experimental nuclear reactor, the . That year, she defended her thesis at the M.V. Lomonosov Institute of Fine Chemical Technonogy, using research from the Radium Institute. In 1945, she headed works at a pilot factory in the city of Elektrostal to manufacture uranium ingots. She was referred to as the "Russian Madame Curie." Seeing the need for a research institute with a wider technical and scientific scope - there were only two institutions (Giredmet and RIAN working with radioisotopes) - she raised the idea with her superiors, initially to the ire of Khlopin.