Many environmental forces changed over the past 4 billion years in shaping life on Earth including magnetic fields and radiation -- but gravity has remained constant. In space, the gravitational forces acting on an organism can be a million times lower than any organism has experienced throughout Earth's history. The last time life encountered an environmental change of this magnitude was when the first organisms emerged from the sea to the land.

Generations offers an unprecedented opportunity to scientifically document one of the greatest evolutionary transitions of all time with all the tools of modern science. Generations proposes to correlate changes in genes and genetic expression in space with physiological causes and consequences in simple living systems over multiple life cycles. This use of space as a powerful biological probe will develop scientific knowledge important not only for space exploration but for life on Earth. Read Full Text.