Mars

The next planet out, the furthest rung most pilots aim for, and a place with just enough air to notice and not nearly enough to land on.

The numbers

These are the figures the map's card shows when you hold your finger on Mars, plus the two speeds that decide what a flight there costs. Low orbit speed is how fast you must be going, sideways, to stay up just above the surface. Escape speed is how fast you must be going to leave altogether. Sphere of influence is how far Mars's pull reaches before something bigger takes over.

Stationary orbit is the height where one trip round takes exactly one of the world’s days, so a ship there hangs over the same spot on the ground. See Stationary orbits.

What it is made of

What the world is built from. It is not something a ship measures, but it is why the ground looks and behaves as it does — an ice moon takes an impact differently from an iron one.

The air

Almost pure carbon dioxide at less than a hundredth of Earth's pressure. It is thin enough that a parachute is nearly decoration and thick enough that a fast entry still heats a hull, which is the worst of both. Near the ceiling the mix breaks down into carbon monoxide and atomic oxygen.

Pressure falls off as you climb: every 7,694 m of height, there is half as much air around you. A Barometer reads that fall directly, and a Thermometer reads the cooling beside it — 2.5 K for every kilometre, until the air bottoms out at 140 K (−133 °C) and stops getting colder.

What the air is made of

The mix changes with height. Each column is a measured level; between two of them the game blends one into the other, and above the top one there is nothing left to breathe. A Mass Spectrometer reads this table itself: its figure is the mean molar mass of the mix where the reading is taken, and beside it the line names the biggest gases it found. See the Mass Spectrometer.

Clouds

Cloud decks stand at fixed heights. The lower one is drawn wherever you fly; the upper one only over the damper ground. You climb through them on the way up and see them from above afterwards. A cloud is drawn in front of your ship: inside a thick one you lose sight of it until you fly out, so pick your way round the big ones. Mars's air is dry, so its clouds stay thin — smooth lenses, rows of small cloudlets and pale sheets in the lower deck, straight wisps and hooked strands in the upper — drawn in Mars's own dusty colour.

The ground

Seven biomes, taken from the picture of Mars that the map draws: the ground you fly over is the rim of that picture. They are not evenly cut: the plains around the world's 0° run only a degree and a half either side, the plains come round again across the whole south, and the ice lies in two places — the North Cap from 140° to the far side, and a narrow shelf under the South Cap. The volcanic highlands are the roughest ground on the planet at 2,600 m of relief, and the canyons the deepest at 400 m below the datum.

Where is the band's place round the world, in degrees from the world's own 0°, running out to ±180° on the far side. Typical height is where that biome's ground sits against the datum the map measures altitude from, and roughness is how far it wanders either side of that.

Named landforms

Mars's ground is drawn from a table of named features rather than noise alone, as every world you can stand on is. Where you come to rest is recorded by name, which is why some achievements ask for a summit, a crater floor or a plateau rather than just a landing. All 17 of them are below, in order round the world — 0° lies on the plains, and the list runs from the far side of the world back to it and on round.

Height is how far the feature stands above the ground around it, or below it where the figure is negative. Flat ground is how much level ground it offers at the top or on the floor — which is what decides whether a lander can stand on it. The ground at the world's own 0° is kept dead flat for the first fraction of a degree.

Its moons

Two moons go round Mars, all of them inside its sphere of influence. Each has a sphere of its own, so the trip from one to another is a small transfer inside the big one.

Getting there

It has air, and not enough of it. Pressure at the surface is under a hundredth of Earth's, so a canopy barely slows a lander and the touchdown is flown on the engine as if there were no air at all. Getting down costs more than the Moon's landing, and getting there costs more again. Landing pays Dust on the Legs.

What a ship leaving Earth's pad needs, in total change of speed, to do each of these:

What it pays

Every place nobody has measured before pays discovery the first time an instrument reads it, and how much depends on how far from home the world is. Mars counts as 3.52 against Earth's 1.00, so every place on it pays that many times what the same place at home would.

A place is a world, a band of altitude and — on the ground — the biome you are standing in, and each instrument surveys each place separately. Science and readings explains the whole of it.

What it pays out for

Mars is named by 7 achievements: Martian Weather Report, Red Planet, Around the Red Planet, Dust on the Legs, Martian Cold Snap, Assembly, Mars Orbit, Ninety-Five Percent Carbon Dioxide. There are also two hidden achievements here, which you will find by flying.

The full list, with what each one pays, is on the Achievements reference.