LEGO Life on Mars was a short-lived LEGOtheme from 2001, and a subtheme of LEGO Space. Basically, a small group of human astronauts crash-landed on Mars, discovered Martians, and sat down and observed them for a while. It is unusual among LEGO Space themes for its stronger focus on exploration and discovery over combat, the human astronauts had no interest in conquering the martians and instead preferred to observe their lives.This was the last true LEGO Space theme for several years, until its Spiritual SuccessorLEGO Mars Mission turned up in 2007. Unrelated to the TV show Life On Mars, though that would be awesome in its own right. Provides the Martians for Irregular Webcomic!.
All There in the Manual: The majority of the theme's storyline could only be found the website. The LEGO Mania magazine also provided extra information, such as revealing that Cassiopeia is Riegel's daughter.
All Myths Are True: Sort of. Remember all the panic that was caused by people who thought that a 1938 radio drama of The War of the Worlds was a true story? It was. Arcturus was leader of Mars at that time, and he actually did invade Earth and was forced to retreat after being exposed to Earth germs.
Combining Mecha: A more unconventional example: all sets were designed to be consistently segmented and modular, and all instruction manuals point out that the modular segments are interchangeable between sets. Also, most of the Martians' sets are mecha.
Humanoid Aliens: Though, discounting Rock Monsters, the Martians were the first LEGO alien lifeforms to depart from the standard Minifigure design.
Humans Are Special: Defied by Riegel, who seems unconvinced of the intelligence of highly-trained astronauts.
Riegel: "So you say you are Earthlings? Are you an intelligent species?"
Mac: "Of course we are! We built a rocket ship and came here, didn't we?"
Riegel: "You came here, but maybe you didn't build the ship. Maybe you are just test animals. After all, some Martians believe that creatures with - ugh! - hair on their heads must be stupid, since the sun never warms their brains enough."
Humongous Mecha: Most of the Martians' vehicles are mecha, and almost all of them have some mechalike traits.
To the 1999 "Space Port" sub-theme; Buzz Bailey from the Space Port line is the same character as BB from Life on Mars. The book Rocket Rescue even says that Buzz Bailey was training for a mission to Mars.
LEGO Racers 2 implies that Life on Mars might also be a Stealth Sequel to the LEGO Arctic line, since the game identifies an identical-looking scientist on the Arctic team as "Doc".