Mars, also known as Sol 4 or Sol d, was the fourth planet in Sol System and the first planet beyond Earth inhabited by Homo sapiens. The model the Class-M designation for planets, Mars had a thin atmosphere, no magnetic field, and low gravity. It is also a core world in the Compact.

Because of the water content below the surface and at the poles, as well as the relative ease of creating oxygen from elements present, Mars is humanity’s oldest and longest running terraforming project.
First reached by Terran humans in the late World War Era and colonized shortly thereafter, Mars became a founding member of the Compact.
Statistics:
Pronunciation: marz
Adjectives: Martian
Also known as: Sol 4, Sol d, the Red Planet, the Fourth Planet, the Citizens’ Republic
Class: M
Star: Sol
Orbit: 206,700,000 – 249,200,000 km
Diameter: 6779 km
Gravity: .376g
Atmosphere: 95.97% carbon dioxide, 1.93% argon, 1.89% nitrogen, 0.146% oxygen, 0.0557% carbon monoxide, 0.0210% water vapor, 0.0100% nitrogen oxide, 0.00025% neon, 0.00008% hydrogen deuterium oxide, 0.00003% krypton, 0.00001% xenon
Political Status: Core World, permanent member of the Compact Security Council
Government: Social democracy – Citizens’ Republic of Mars, founded 98 IE
Primary Polity: Compact of Humanity in Assembly
Appearances: No Marigolds in the Promised Land