Understanding Martian Timekeeping

Time moves differently on Mars.

A single Martian day — known as a sol — lasts 24 hours, 39 minutes, and 35.244 seconds, slightly longer than an Earth day. A Martian year, measured by its orbit around the Sun, spans 668.6 sols, or approximately 687 Earth days.

The current scientific standard for tracking Martian years begins with Mars Year 1, defined by NASA and the Mars Climate Database (MCD) as starting on April 11, 1955 (Earth date). Since then, each Martian year is counted consecutively.

In The Mars Chronicles, the story opens on Sol 117 of Mars Year 73, which translates — according to the MCD system — to:

📅 Earth Date: January 10, 2091

That’s where Icarus begins.

The story spans about one Earth year, unfolding through a volatile period of Martian colonization as fragile settlements struggle under both political pressure and environmental degradation.

We follow the Mars Sol date system throughout the book, anchoring each major event in Martian time — because when survival depends on atmospheric conditions, solar energy levels, and orbital windows, every sol matters.