Temperature & habitability

When generated, every planet receives an equilibrium temperature derived from its orbital position and its star's luminosity. That temperature then drives habitability — which in turn modulates the available fields — and the yield of your Deuterium Synthesizer.

Temperature calculation

Spacy uses a Stefan-Boltzmann variant: equilibrium temperature depends on the star's luminosity (L, indexed against the Sun) and the orbital radius (r, in astronomical units). The result is then converted to degrees Celsius.

  • L: star luminosity index (Red Dwarf ×0.04 → Blue Giant ×30,000)
  • r: planet's orbital radius, in AU (the closer to the star, the hotter)
  • 288 K (~15 °C): reference temperature of an Earth-like planet orbiting at 1 AU around a Yellow star
  • Exponent 0.25 (fourth root): dampens irradiance to avoid unrealistic extremes

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Day/night and atmosphere swings

Once the equilibrium temperature is computed, two random effects are applied during planet generation:

  • Greenhouse effect: the equilibrium temperature is multiplied by a random factor between 0.8 and 1.2 (more or less insulating atmosphere)
  • Day/night swing: a minimum and maximum temperature are then derived by adding or subtracting 30 to 60 °C
  • This min/max range is what's displayed on your planet and used in all calculations (notably the deuterium factor)

How habitability is judged

A planet is rated Habitable, Semi-habitable or Hostile based on an internal score computed from three weighted criteria. The higher the score, the more welcoming the planet.

  • Average temperature (weight —%): ideal between — °C and — °C, tolerated between — °C and — °C
  • Surface gravity (weight —%): comfortable between — g and — g, bearable between — g and — g
  • Mass (weight —%): the planet must be massive enough (at least — Earth mass) to retain an atmosphere

Temperature veto

If the average temperature falls outside the tolerated range (— °C to — °C), the planet is immediately classed Hostile without any score calculation — regardless of gravity or mass. That's the physical limit beyond which no colony can survive.

  • Score ≥ — → Habitable
  • Score between — and — → Semi-habitable
  • Score < — → Hostile

Effect on available fields

Habitability then multiplies the planet's natural buildable field count:

  • Habitable: +—% available fields
  • Semi-habitable: no bonus, no malus
  • Hostile: −—% available fields

Effect on deuterium production

Deuterium Synthesizer yield is highly temperature-sensitive. The colder the planet, the higher the factor; the hotter, the lower it drops, down to a floor of —× for extreme temperatures.

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A few examples

  • T_max = 0 °C: factor ×1.36 (+36% production)
  • T_max = 50 °C: factor ×1.16 (+16%)
  • T_max = 100 °C: factor ×0.96 (−4%)
  • T_max = 200 °C: factor ×0.56 (−44%)
  • T_max ≥ 215 °C: floor at ×0.5 (−50%, guaranteed minimum)

Important

Temperature currently has no other in-game effect: it does not modify solar plant output, fusion reactor output, or combat stats. Its impact is limited to habitability (and therefore fields) and to the deuterium factor.