Styx

Styx

Orbital characteristics
Mass (Kg)	2.68E+23
Radius (Km)	1,925
Solar Day (h)	48
Orbital Period (days)	2
Semi-Major Axis (Km)	356,801(km)
Periapsis (AU)	.002
Apoapsis (AU)	.002
Albedo	0
Surface Temperature (K)	147
Surface Gravity (m/s^2)	4.84
Axial Tile (degrees)	2.4
Inclination (degrees)	0
Orbital Speed (Km/s)	6.34
Satellites	None

Styx is the first of the three major moons of the planet Thalassa.

North Polar Regions

A labelled map of the surface of Styx.

The surface of Styx, unlabelled.

The North Polar Regions of Styx are dominated by a fractured and uneven ice cap that rests upon older, darker terrain. Unlike a uniform polar sheet, the northern ice is broken by deep fissures, exposed rock, and irregular uplands, producing a sharply divided boundary between frozen and uncovered ground. Along the northwestern transition, the rugged highland system known as the Kethar Marches forms one of the most unstable regions of the polar boundary, where ice fractures into jagged shelves and exposed ridges.

South of this boundary, the large enclosed depression called the Phoenor Basin marks one of the most prominent northern basins, its dark interior standing in contrast to the surrounding frost. Nearby, the elevated circular formation known as the Acheronax Crown rises above the surrounding terrain as one of the defining structures of the northern hemisphere. To the east, the boundary zone termed the Nyxis Verge marks the transition into more broken and partially uplifted terrain, where the polar ice gives way to the darker and more varied equatorial belt.

The northern hemisphere is therefore characterized by fragmentation and threshold conditions. Ice and exposed ground interlock across a landscape shaped by stress, collapse, and long-term erosion. The Kethar Marches, Phoenor Basin, Acheronax Crown, and Nyxis Verge together define a region where surface and depth meet in unstable equilibrium.

Equatorial Regions

The Equatorial Regions of Styx are dominated by dark plains, immense impact basins, and broad streaks of lighter surface material spread across the low latitudes. Much of the equatorial belt consists of very low-reflectivity terrain, broken by large circular depressions, degraded crater walls, and isolated rough uplands. Sweeping bands of pale dust or frost-stained material extend across the middle latitudes, giving the equatorial zone its most distinctive large-scale pattern.

Several major basins define this region. One especially large circular depression dominates the eastern equatorial belt, while other broad crater floors and partially buried basins extend across the central and western low latitudes. The lighter material is concentrated in long diffuse streaks and basin-margin deposits, indicating widespread transport and redistribution across the surface. The equator contains the broadest uninterrupted exposures of Styx’s dark rocky crust and preserves much of the moon’s large-scale impact history.

Southern Polar Regions

The Southern Polar Regions of Styx are brighter and more extensively ice-covered than much of the equatorial surface. Broad frozen plains, fractured ice-rich deposits, and rough rocky interruptions extend across the southern high latitudes. The southern cap is uneven and broken, with enclosed basins, exposed ridges, and dark cratered masses projecting through the frozen terrain.

The transition from the southern polar ice to the darker middle latitudes is highly irregular. Ice and frost collect in low basins, spread across broken plains, and gather along the margins of rough terrain, while exposed dark ground remains visible across much of the polar boundary. This gives the south a more complex and varied structure than a single continuous cap. The southern hemisphere combines permanent frozen deposits with ancient impact-scarred terrain and broad zones of fractured ground.