A planet untouched by the Gamilon threat, Mars is used by the Earth Defence Force as a training ground for cadets, most notably Susumu Kodai and Daisuke Shima. The surface gives off a reddish hue due to oxidized iron within the Maritan soil. The atmosphere is very thin and is unsuitable for a Humans and Iscandarians without terraforming or a creation of man-made shelter. The planet is terraformed at some point and had at least one ocean. Prior to 2199, two battles were fought above Mars. Admiral Juzo Okita is noted as a hero at the Second Battle of Mars, which stopped a direct Gamilas assault on Earth with warships, causing the deadly planet bombs to be used to attack instead. On January 17, 2199, Sasha Iscandar crashes on the planet and is found dead by Kodai and Shiima. They recover the wave motion core she was carrying and bury her on the planet. The Yamato also uses it as a destination in the first test of its warp drive, and lands there to conduct repairs on its hull.
- In the 2199 series, Akira Yamamoto states that she is from a long generation of people of Mars, as told by her eye color, red. This cause the assumption that she lives in a man-made structure and Mars was not terraformed as this adaption would not happen with thicker atmosphere, as red is insensitive to light. Despite that she also have white hair along with her red eyes, she is not an albino as her skin is the same tone as non-albino, indicating that she, like most Japanese anime, is using a hair dye.
- Despite being confirmed to be terraformed in the 2199 series, the planet's atmosphere is not safe for human habitation. This would imply that Mars may have also been hit with planet bombs, or the area where Kodai and Shiima were was at higher elevation where the atmosphere was thinner.