Marius Regio
What Marius Regio is
Marius Regio is a regio — a large area distinguished by its brightness or colour — on Ganymede, 4,940 km across, centred at 2.5° N, 172.3° E. It is the 2nd largest named feature on Ganymede and the 1st largest of its class there.
Where the name comes from
Simon; German astronomer (1570-1624). The International Astronomical Union approved the name in 1979, under the theme it applies to every regio on Ganymede. Of the 6 features of this class catalogued on Ganymede, the naming categories run American (3), Germany (1), Italy (1), England (1).
What it would take to settle Marius Regio
Ganymede scores 55 as a world. That number is the same for every square metre of it — but sunlight, water, radiation and the ground under your feet are not. This is the same question asked at 2.5° N, 172.3° E.
What this spot has going for it is radiation geometry — under closed field lines, the shielded part of the only magnetosphere on any moon. What works against it is temperature — about -156 °C mean at this latitude.
Computed from Marius Regio's catalogued latitude, longitude and feature class — 84% of the model's weight had a basis here, and 2 axes were dropped as not applicable to Ganymede (earth link, known ground). Gravity, pressure, delta-v and distance from the Sun are the same everywhere on Ganymede and are already counted in the world's own index, not again here.
What this cannot see: elevation. Slope, local shadowing and the polar “peaks of eternal light” — ridge tops near the poles of a barely tilted world that catch sun almost continuously while a crater floor kilometres away never does — need a terrain model this does not have. Where a real mission targets a pole, that is usually why.