Environment and weather

The planet keeps time

Every world runs a day–night cycle and a longer environmental rhythm on top of it. Light matters mechanically — a Solar Array lives and dies by it, and so does the Habitat, whose own array is the grid a young colony runs on — and temperature swings between day and night can be brutal on the archetypes that run hot or cold.

While the sun is up, output is steady — the day has no better or worse hour, only a latitude, and the one thing that dims it is the sky. Cloud over a site takes a bite out of every panel under it, and a storm overhead takes a large one.

On the unlit side of a world, solar output is not reduced. It is nothing. Whatever the colony spends after dark comes out of a Battery Bank, or off a plant that does not need the sun at all — geothermal, a reactor, a generator burning something you had to make first.

The environment is deterministic for a given seed and turn: the weather is not rolling dice against you. A colony that pays attention can genuinely plan around what is coming.

Deciding what the night costs

Because the reserve is finite, the colony declares who is allowed to spend it. Every consumer sits in a power band, and the settlement sets how deep into the battery it will reach: bands at or above that line keep running through the night, bands below it live on surplus production and switch themselves off at dusk.

That makes darkness a scheduling problem rather than an emergency. Life support and housing ride the reserve; a smelter or a laboratory waits for morning, and nothing is lost by letting it. You can also park an individual building outright — it keeps standing and keeps its storage, but stops drawing — or throw the whole settlement into conservation mode, which keeps survival systems alone and lets the battery recover.

What the climate costs to hold off

A world that sits far from comfortable does not merely look hostile — it bills you, every turn, forever. Holding a settlement at a temperature people can live in is a standing energy cost, and on the colder and hotter archetypes it can dwarf everything else the colony spends put together. This is the single largest reason one landing site is worth more than another.

The bill arrives in two parts. Keeping the people themselves alive is not negotiable and cannot be shed: a brownout may darken a workshop, it will not switch off the heating. Every other module pays its own surcharge on top, scaled by how big it is, how much of it is heated interior, and how exposed its shell is to the outside — and that half a brownout will shed, so a cold night puts out the heated workshop long before it touches the habitat.

Cold and heat are not symmetric. Heating scales gently with the gap, because insulation is passive and anything the colony burns turns into heat anyway. Cooling has to push heat uphill into an ever-hotter sink, and there is nothing you can burn to get cold — so a hot world of a given severity costs more than a cold one.

None of this is a fixed property of a square. It moves with the season, and it moves with the weather: a front standing over a site strips heat where it is already freezing and traps it where it is already baking, so the bill always gets worse while the storm is overhead and eases when it passes. Every place reports its own reading, along with the range it will swing through across a full year — read that range rather than today’s number, because you will still be standing there in winter.

And no two worlds keep the same calendar. Each planet runs its own cycle of seasons — how many there are, how hard the swing bites, and where in the cycle you arrive are all facts of that world, with each archetype keeping a character of its own. The colony does not know the cycle at landfall: at first the instruments state only whether its own sky is warming or cooling, two years of records name the seasons and place the world in its cycle, and only planetary climatology charts the full model — the swing, the latitude ramp, and the lengths.

Crews in the open

A settlement is a buried, insulated mass with a battery; it averages the day away. A field team is people and a vehicle standing outside, and it feels everything the settlement shrugs off — the season, the night, and the front overhead. On a hostile world the difference between noon and midnight is a real operational fact.

The only thing between a person and that is what they are wearing. There is one field suit and it answers everything at once — heat and cold, the atmosphere, the radiation — competently at all of it and brilliantly at none, with what it is made of deciding where it is strong. A pressurized rover cabin is better still, and it covers everyone it seats.

Air the crew cannot simply breathe splits into two kinds, and they ask for different things. Air that is unbreathable but dense enough to stand in is answered by a breathing apparatus straight from the carried oxygen — part of every crew’s field kit, no suit required; the only question such a trip asks is whether enough oxygen rides in the hold. Air too thin to stand in is a different matter entirely: there the environment itself demands a sealed suit on every head, and no amount of carried oxygen substitutes for it — pressure, not breath, is what bites.

A suit covers its wearer and nobody else. That is the whole shape of the decision: a crew three suits short has three people out in it with nothing, and the unit card names the worst off of them rather than averaging the crew into a comfortable single number. How many suits the colony holds is therefore a real ration — where the air merely stings, it decides how many people go out unprotected; where the pressure or the temperature demands the suit, it decides whether they go at all.

Heating is neither free nor absolute: it runs off the energy the team is carrying, and in a true extreme it runs flat out and still loses. The chemical and radiological barriers cost no power at all — there is nothing to run — but they are no more absolute for it.

Whatever the suit cannot hold off lands on that person. Their work slows, their injuries become markedly more likely, including the kind that leave something permanent behind, and a poisoned sky makes them ill on top of it. Inside the survivable band nothing forbids you from sending a team anywhere; the planet simply charges you for it, and it charges you by the head. Past the band’s edge the planet stops charging and starts refusing: ground beyond the survivable temperature takes a suit on every head and carried energy to keep them running, and an order that would put people out there without either — like a march through air too thin to stand in with an unsealed head aboard — is turned down by name before anyone moves. A battery that dies on the way kills nobody; the cover stops and the familiar penalty returns.

Weather as a condition of work

Weather regimes differ by world and by region — dust, storm, cold snap, each with teeth of its own. Conditions modify what field work costs and what it risks: the same route is a different proposition in clear air and in a storm front. Hazardous ground plus hostile weather is where crews are lost.

Reading the world in real units

What the planet measures, it reads the way the real world would. The planet profile states the pressure at the surface in pascals — an airless rock reads nothing at all — and the panel of any place you have revealed states its radiation as the dose an unprotected person would take there in a year, in sieverts, beside the prevailing wind in kilometers an hour. That wind is the same one that carries the storms across the map.

The ground reads the same way: distance in kilometers, relief in meters, the extent of a named range or crater in square kilometers, and a vehicle by the kilometers a day it covers over open ground. A unit changes how a value is written, never what it does — the warning tones sit where they always sat, and indexes with no physical twin, such as toxicity, stay the plain shares they are.

The living cover

Vegetation is not a painted backdrop: it is a living field that grows toward what each place can carry, thins with winter and polar night, and retreats under whatever the colony builds. Even snowbound polar ground carries a thin cold-adapted crust, and open water grows a cover of its own — a plankton shelf, richest over the shallows, its seasons softened by the sea’s inertia. Sunlight is not its only table either — where a planet’s own heat reaches the surface, on land or on the sea floor, the cover can live off that instead, untouched by season or night; and on worlds with no green cover at all, even the dead ground carries a thin energy substrate the environment keeps renewing — photochemical fallout on frozen worlds, slow crust chemistry on airless rock — so life spreads thinly across the whole surface, with the heat-fed mats as its richest oases. Ground under settlements and roads reads as cleared; once a structure is abandoned, the cover creeps back over years, so a colony leaves visible scars and watches them heal.

The Biosphere mode of the planet lens reads the field — live values only where the colony has surveillance, the ground-survey estimate over walked land, and nothing at all over ground neither watched nor walked. The sector, region and location panels state the same cover as a Biomass reading beside moisture, under the same rule: live where you watch, the walked-ground estimate where you do not, no reading with neither — and the reading says which.

And the cover is lived off: every world draws its own cast of species — grazers, foragers, carrion-eaters and hunters, each kind at home in its own stretch of country — so no two worlds carry the same fauna, and the wild replenishes itself: a species thinned toward nothing finds its way back from the edges of its range in time. They live as individual creatures with inherited, evolving ways. Herds graze scars into the field, scavengers follow the dead, and where the planet’s own heat breaks the surface, some lineages skip eating altogether and drink the vent’s energy directly — a colony of them huddled on a rift is a way of life the species record names, and it is why a dead world’s vents read as the rich cores of its thinly living surface. What a creature eats is not everywhere the same meal either: the flora of a tundra is not the flora of a desert, and a lineage tuned to its home ground digests it better than any wanderer — which is what makes species belong to their biomes. The colony enters their senses like anything else in their world: most learn to avoid its noise, some probe its perimeter, and an attack on a field team is the act of a real creature — the fight that follows is against those bodies, not against a hazard number. Water and land are two elements with a hard coastline between them: sea lineages and land lineages each evolve in their own world, and neither crosses the shore. On the map, wildlife shows only where you hold surveillance — and obeys the marker rules like any other group; a region or sector record lists the species in sight.

What the colony learns of them, it earns: the first sighting writes a species into its book under a code, a scientist on a standing field study reveals its ways and eventually earns it a name, and a standing hunt turns wildlife into a trickle of food — every kill a real body taken from the world, part of it left where it fell for the scavengers.