Chapter 24: Satellites of Théxar — Serrin and Thel
"Two moons — two eyes of the night. Serrin — wise, full, looking forward. Thel — swift, wild, looking backward. Together they illuminate our darkness." — From "Song of Two Moons," Xha'Ruun folk poetry
Related sections: → see [Ch.03, "Planet Théxar"], → see [Ch.16, "Magnetosphere"], → see [Ch.19, "Resources"] Key principle: Théxar has two satellites: Serrin (large silicate moon) and Thel (small dark moon). Serrin — stabilizer of the planet's axis and source of tides; Thel — main source of He-3 for fusion energy.
24.1 Serrin
The largest satellite of Théxar. Probably formed simultaneously with the planet from the same protoplanetary disk (co-accretion hypothesis), rather than as a result of a collision.
24.1.1 Physical Parameters
| Parameter | Value |
|---|---|
| Albedo | 0.12 |
| Surface T (day) | +91.3°X |
| Surface T (night) | −25.6°X |
| Rotation period | Synchronous |
24.1.2 Orbit
The moon’s motion is tracked against the stars and Théxar.
24.1.3 Surface
Serrin is a typical silicate body covered in regolith. Basalt plains (maria) occupy ~35% of the visible side. The largest crater — Ven-Khal (diameter 36.6 мо), located on the far side.
- Serrin Maria: 4 large basalt basins
- Craters: >10,000 with diameter >0.20 мо
- Surface age: 4.2–3.5 billion cycles
24.2 Thel
Théxar's second satellite — a captured C-type (carbonaceous) asteroid, captured by the planet's gravity ~2.5 billion cycles ago.
24.2.1 Physical Parameters
| Parameter | Value | Note |
|---|---|---|
| Albedo | 0.04 | Dark surface |
24.2.2 Orbit
The moon’s motion is tracked against the stars and Théxar.
24.2.3 He-3 — Strategic Resource
Thel is the main source of helium-3 for Xha'Ruun fusion energy.
| Parameter | Value |
|---|---|
| He-3 concentration in regolith | 0.002–0.005% (by mass) |
| Total reserves | ~60.6 million кх |
| Annual extraction | ~485,000 кх |
| Availability | ≈125 years at unchanged extraction (at current level) |
| Extraction cost | 2.1 cents/kWh (final) |
Extraction is carried out by automated stations on Thel's surface. Regolith is heated to 425.7°X; the released He-3 is collected, liquefied, and sent to Théxar.
24.3 Tidal System
The combined influence of Serrin and Thel creates a complex tidal regime.
| Parameter | Serrin Influence | Thel Influence | Combined |
|---|---|---|---|
| Tide height (max) | 2.2 ша | 0.37 ша | 2.6 ша |
| Tide height (avg.) | 1.1 ша | 0.12 ша | 1.2 ша |
Tides on Théxar have an average height of 1.2 ша, due to the small mass of the satellites.
24.3.1 Tidal Deceleration
Serrin is gradually moving away from Théxar at a rate of ~1.4 па/year. Théxar's rotation slowdown is ~0.002 s per century.
24.4 Phases and Eclipses
24.4.1 Phases of Serrin
Serrin’s phases change with the relative positions of the moon, planet and star. Synchronous rotation keeps predominantly the same side facing Théxar.
24.4.2 Solar Eclipses
A solar eclipse occurs when Serrin crosses the disk of Khar’Vex. Its appearance depends on the observer’s location.
24.4.3 Lunar Eclipses
A lunar eclipse occurs when Serrin enters Théxar’s shadow.
24.5 Exploration
| Object | First Expedition | Permanent Base | Population |
|---|---|---|---|
| Serrin | +1,200 Y.E. | +2,400 Y.E. | ~800 people |
| Thel | +2,100 Y.E. | +3,300 Y.E. | ~200 people (shift) |
24.5.1 Serrin-1 Base
Located in the Ven-Khal crater (36.6 мо, far side). Scientific station, telescopes, He-3 mining control center on Thel.
24.5.2 Thel Mining Complex
Automated complex on Thel's surface. Area — 4.96 мо². Consists of 24 drilling stations, 4 processing plants, and a spaceport for sending He-3 to Théxar.
Chapter Summary
- Serrin — large silicate satellite, stabilizes Théxar's axis.
- Thel — captured C-asteroid, source of ~60.6 million кх He-3.
- Tides have an average height of 1.2 ша.
- He-3 extraction on Thel: ~485,000 кх/year, availability ≈125 years at unchanged extraction.
- Permanent satellite population: ~1,000 people.