Science Fiction - Silent Running

By the year 2008, all that remains of the Earth's plantlife is preserved in space, maintained under huge Geodesic domes on board three ships orbiting the planet Saturn. Botanist and crewman Freeman Lowell (Bruce Dern) is horrified when the order comes from home to destroy the greenhouses, and kills his three human crewmates in order to prevent them from carrying out the termination. Injured in the process, Lowell is forced to rely on his three service robots as he goes on the run in the one remaining station, determined to preserve what is left of his home planet's ecology.