Today’s space technology seems profoundly inspired by science fiction novels. The endeavor of deep space exploration is based on speed and rocketry. Many try to design and produce space vessels which will travel with very high speeds, because science fiction writers always describe travel between stars at high speeds. A typical space ship is furthermore aerodynamic (usually flying saucers) and equipped with life supporting systems which recycle oxygen and other excretes. The typical spaceship is modelled to provide all the ecosystem services (breathing air, water, food, etc.).
If you design space ships like the planet Earth, they are doomed to very short voyages. Secondly, the typical spaceship does not provide a very important extraterrestrial ecosystem service, that is sunlight. Sunshine is a prerequisite for healthy human life. A design of a space vessels needs to include artificial sun by considering circadian rhythms. The artificial sun as technology will allow for multigenerational journeys in deep space. It is a design and technological challenge that is not explored yet. The Earth is a spaceship and closed system (biosphere), but without the Sun most of life will disappear in matter of weeks.