Boris Yegorov (1937-1994) was a Soviet physician and cosmonaut. Son of neurosurgeon Boris Grigoryevich Yegorov, he studied medicine before being selected for the cosmonaut programme. In October 1964, he flew aboard Voskhod 1 as the flight physician, becoming the first doctor in space. His mission was to study the crew's physiological responses during weightlessness, a foundational contribution to Soviet space medicine.