Fedir Tetyanych (*1942, Kniazhychi, †2007, Kyiv, Ukraine) was a visionary artist who worked with painting, sculpture, and performance. He was influenced by cosmism, cybernetics, rural Ukrainian traditions, and ecology. Born in Kniazhychi near Kyiv, he explored the unity of humans and the universe, using ideas from science fiction and scientific research as well as Ukrainian folk traditions, cosmologies, and history, focusing on the Cossacks. He was commissioned to create works on monumental mosaics and decorative panels, while he engaged in his own theoretical and permeative practice in his free time. One of his central concepts was the Biotechnosphere. This was a universal, self-sufficient module shaped like a sphere with a radius of 120 centimeters. He imagined it as a space for living, shelter, transport, and rescue. When connected with other modules, the Biotechnosphere would grow into larger structures. Tetyanych wanted a sustainable model of coexistence, not domination by technology. His view of the cosmos was distinctly humanist. Unlike Russian cosmism, which wanted to change the earth for future humanity at any cost, he rejected the destruction of existing life. He described his existence as an ongoing performance stretching from the earth to infinity, in which he presented actions and wrote cosmist and ecological manifestos. His avant-garde work is a local response to broader ideas about science and technology and their hopeful possibilities. It reflects the environmental awareness and futurological imagination that emerged during the global Cold War.