Here we clearly see the hexagonal structure of the Discovery One spacecraft from 2001: A Space Odyssey. The engine housings as well as the connective structure between the engines and the habitation spheroid have an overtly hexagonal form to them.
Here we see the hexagonal architecture of the International Space Station's Cupola module. Hexagonal space-windows are often seen in science fiction treatments of space travel, but this is the first time we have seen a proper full-sized hexagonal window in an actual spaceborne craft. The hexagon is of course the natural geometry for dealing with the hostile environemnt of outer space, as we have seen for many decades now in the hexagonal structure of satellites and deep space probes. No doubt we will see more and more such hexagonal architecture as we move out into the Solar System—eventually.