 The station served as a microgravity research laboratory in which crews conducted experiments in biology, human biology, physics, astronomy, meteorology and spacecraft systems with a goal of developing technologies required for permanent occupation of space.The record for longest human endurance on a single tour in space is held by Valeriy Polyakov, who left Earth on January 8, 1994, and stayed aboard the "Mir" space station for a total of 437 days, 17 hours, 58 minutes, and 16 seconds, returning March 22, 1995.Sergei Krikalyov holds the current record for combined total time in space