[1] He was the director of the Kyiv Planetarium, a member of the National Academy of Sciences of Ukraine and the International Astronomical Union,[2] of the New York Academy of Sciences, the editor of the magazine "Our Skies" (Ukrainian: Наше Небо) in 2006–2009, the president of the Ukrainian Society of amateur astronomy and the author of books for children.

In 1969, he discovered, with Svetlana Gerasimenko, the comet 67P/Churyumov–Gerasimenko; on 12 November 2014, the Rosetta[3] space mission landed its Philae spacecraft on its surface.

However, he continued to attend lectures on theoretical physics, even though the authorities disapproved, and he was eventually moved to the faculty of astronomy, where there were vacant places.

In 1962, he returned to Kyiv and went to work at the plant "Arsenal", where he participated in the development of optical components for the Soviet military and space programs.

"[6] In 1993 he defended his doctoral thesis on "Evolutionary physical processes in comets" at the Institute of Space Research, RAS (Moscow).