Since the early days of the opening up of the Soviet Union, Dr Kass has worked with various Russian space agency institutions, a key centre being the Yuri Gagarin Research & Test Cosmonaut Training Centre - GCTC Star City, Russia. He studied how Cosmonauts are trained, how crew procedures are prepared, and the processes of progressing through the various stages of preparation of both the crew and the manned payloads, as well as the operational rules, processes, and methods during the continuous manned operations of the MIR station.

He conducted training of German and NASA astronauts and Russian cosmonauts for operating the Modular Physiological Laboratory, MEDEX, on the MIR-97 mission at Star City. Preparatory testing of MEDEX was performed on the GCTC’s parabolic flight research aircraft, the “Zero-G” Ilyushin 76-MDK.