No surface off Earth is habitable — unprotected, a human dies on every one of them in minutes or less. So instead of a habitability percentage, each world is scored on the seven axes a habitat has to engineer its way out of: radiation, pressure, temperature, gravity, water, available energy and the cost of getting there. Every input is a measured or published figure, and the score is computed from them — nothing here is a rating somebody typed in. Mars comes out easiest at 26.6; Io is the wall, at 76.7.
| World | Gravity | Mean temp | Radiation | Water | Travel time | Map at |
|---|---|---|---|---|---|---|
| Mercury | 0.38 g | 167 °C | — | confirmed | 6.6 years | 166 m/px |
| Venus | 0.90 g | 464 °C | 0.001 mSv/day | none | 4 months | 75 m/px |
| The Moon | 0.17 g | -20 °C | 1.37 mSv/day | confirmed | 3 days | 100 m/px |
| Mars | 0.38 g | -63 °C | 0.640 mSv/day | confirmed | 7 months | 232 m/px |
| Phobos | 0.00 g | -40 °C | 0.700 mSv/day | unknown | 7 months | ~5 m/px |
| Vesta | 0.03 g | -83 °C | 0.600 mSv/day | none | 3.9 years | ~60 m/px |
| Ceres | 0.03 g | -105 °C | 0.500 mSv/day | confirmed | 7.6 years | ~140 m/px |
| Io | 0.18 g | -143 °C | 36,000 mSv/day | none | 6.1 years | 1 km/px |
| Europa | 0.13 g | -160 °C | 5,400 mSv/day | confirmed | 6.1 years | 270 m/px |
| Ganymede | 0.15 g | -163 °C | 80.00 mSv/day | confirmed | 6.1 years | 359 m/px |
| Callisto | 0.13 g | -139 °C | 0.100 mSv/day | confirmed | 6.1 years | 1 km/px |
| Enceladus | 0.01 g | -198 °C | 0.150 mSv/day | confirmed | 6.6 years | 100 m/px |
| Titan | 0.14 g | -179 °C | 0.010 mSv/day | confirmed | 6.6 years | ~4 km/px |
| Ryugu | 0.00 g | -27 °C | 0.700 mSv/day | none | 3.6 years | ~0.5 m/px |
Nothing here is a texture we painted. Each world streams a live plate-carrée tile pyramid published by NASA Trek and USGS Astrogeology — the same public-domain mission mosaics every space map on the web is built from — draped onto our own sphere, with a higher-resolution patch loaded under the camera as you zoom. The place names are the IAU Gazetteer of Planetary Nomenclature, 15,142 approved names across these 14 bodies.
