In the mid-70s, George Lucas commissioned American illustrator Ralph McQuarrie (1929-2012) to design the world of what came to be the most successful sci-fi franchise of all time. McQuarrie's original design process took him from a female Luke Skywalker to Stormtroopers with their own lightsabers, which were all based on Lucas' early drafts.
McQuarrie's 'used future' look of glued-together starships and lowlife characters - as opposed to the shiny, clean designs of the 60s - still influences sci-fi designers to this day.