PART III - BUILDING MARIAN
An Operating Calendar for Human Mars

The previous Part mapped the choices. Marian now has to make them.

It does so through one governing design principle: Functional Separation.

The idea is simple. When an inherited unit or mechanism performs several useful jobs only because Earth happens to let those jobs coincide, Mars gives us no reason to keep them bundled once those relationships come apart. Preserve the functions that matter; give them different mechanisms when one can no longer serve them well.

Or more simply:

Different jobs deserve different mechanisms.

The clearest example is the month. On Earth, a month can be both roughly four weeks and roughly one twelfth of the year. A quarter can likewise be both one fourth of the year and a useful thirteen-week planning interval.

On Mars, those relationships split apart.

Marian's central move is not to choose one function and discard the other. It gives them different homes. Minths provide the shorter cadence; months provide twelve-part annual orientation. Sixths offer a medium-range interval; quarters preserve the larger annual fraction.

The same principle continues through the rest of the calendar. A complete civil system must also decide how the week recurs, where the year belongs, how the calendar remains aligned with Mars, and how dates retain stable identities across languages and software.

Together, these form the Five Layers of Marian:

Structure — what are the units?
Recurrence — how does the week work?
Anchor — where does the year belong?
Intercalation — how does the calendar remain aligned?
Identity — how are dates represented and preserved?

Chapter 9 shows the architecture as a whole. Chapters 10 to 14 then take those five layers apart, one at a time.