This was the first theme to feature two types of Minifigures: human astronauts (from Lego Town) and Martian aliens (native to Mars). The sets denote peaceful coexistence between the two species on the planet Mars. The "Life on Mars" theme pioneered several unique aspects in Lego in general. It was the first Lego theme to use a pneumatic pump system that was capable of sending Martian Minifigures through tubes in the 7317 Aero Tube Hangar set. This system would later be seen in the "Mars Mission" theme to shoot missiles. The theme also introduced several new muted colors to the Lego color palette, including Sand Green, Sand Blue, Sand Red, and Sand Purple. Sets were designed to separate into segments easily to encourage children to mix and create their own unique vehicles out of both human and alien sets. The Humans had a white and blue color scheme while the Aliens had a variety of colors.