Cosmonaut Valeri Polyakov returns to earth after setting a record of 438 days in space.

An astronaut is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member of a spacecraft. Although generally reserved for professional space travelers, the term is sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and space tourists.

Valeri Vladimirovich Polyakov was a Soviet and Russian cosmonaut. He is the record holder for the longest single stay in space, staying aboard the Mir space station for more than 14 months during one trip. His combined space experience was more than 22 months.

Outer space, or simply space, is the expanse that exists beyond Earth's atmosphere and between celestial bodies. It contains ultra-low levels of particle densities, constituting a near-perfect vacuum of predominantly hydrogen and helium plasma, permeated by electromagnetic radiation, cosmic rays, neutrinos, magnetic fields and dust. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins.