Mars is a planet in the Solar System.
In the 1987 TMNT cartoon The Fifth Turtle, Mars is one of the celestial bodies in the conjunction where Krang uses Capsidium crystals to re-power the Technodrome.[1]
In the TMNT Adventures story The Wrath of the Fire God, the astronomers observe the planet in the beginning of the story, refering to 19th century-early 20th century beliefs about canals on Mars.