The longest single time any human has continuously lived in space is 437 days and 18 hours, and it was done by Russian cosmonaut Valeri Polyakov aboard the Mir space station from 1994–1995.

Longest single stay in space

  • Valeri Polyakov, a Russian cosmonaut and physician, holds the record for the longest uninterrupted spaceflight.
  • He lived aboard the Mir space station for 437 days and 18 hours during a mission from January 1994 to March 1995.
  • His mission was designed to study how the human body and mind cope with extremely long durations in microgravity, relevant for future Mars-length missions.

Other notable “long duration” records

  • NASA astronaut Frank Rubio holds the record for the longest single spaceflight by a U.S. astronaut at 371 days aboard the International Space Station (ISS), set on a mission that ended in 2023.
  • NASA astronaut Peggy Whitson holds the NASA record for most cumulative time in space at 675 days over multiple missions.

Most total time ever spent in space

  • For aggregate time, Russian cosmonaut Gennady Padalka has spent about 879 days in space over five missions, the most cumulative time any person has spent off Earth.
  • More recently, Russian cosmonaut Oleg Kononenko has surpassed the 1,000-day mark in cumulative time in orbit, becoming the first human to cross that threshold.

TL;DR:

  • Longest single stay: Valeri Polyakov, 437 days on Mir (1994–95).
  • Longest single U.S. stay: Frank Rubio, 371 days on ISS.
  • Most total time in space: Gennady Padalka (~879 days), later surpassed in total days by Oleg Kononenko (over 1,100 days).

Information gathered from public forums or data available on the internet and portrayed here.