Evolution in space: experimental pathways to understanding life’s adaptability beyond Earth

Abstract Understanding how life might evolve beyond Earth is a long-standing question in astrobiology. While significant advances have expanded the search for potentially habitable exoplanets, the biological and evolutionary processes that life may undergo in extraterrestrial environments remain largely speculative. Despite early recognition of its importance, experimental studies on evolution in space and analogue environments (AEs)—particularly involving multicellular organisms—have been limited. This gap is due in part to the difficulty of replicating complex space and other planets’ conditions, such as microgravity, high salinity, pressure and/or radiation, on Earth. Recent spaceflight and AE experiments, however, have begun to yield critical empirical data. In this review, we integrate theoretical and experimental data from Earth and space studies to explore the evolutionary trajectories life might take beyond Earth. We interpret current knowledge from ground-based, spaceflight and AE biological studies across a wide range of organisms, and emphasize the need for multigenerational studies for accurately predicting and detecting diverse forms of life beyond Earth.