Warp drives

A warp drive closes a bubble round your ship and puts it where its own orbit would have carried it after a span you choose. No clock moves. Everything else in the solar system stays exactly where it was, and the crew live every hour of it. It buys time, never speed.

What a warp actually does

Think of it as fast-forwarding one ship and nothing else.

You set a span — four hours, a day, a month — and form the bubble. Your ship jumps forward along its own orbit to the point that orbit would have reached after that span. Then the bubble opens, and you are flying again from there.

Four things follow, and all four matter:

• No clock moves. Not the world's clock, not your phone's. It is the same moment when you come out as when you went in.
• Nothing else moves either. Every planet, every moon and every other ship is exactly where it was. That includes your own other ships.
• The crew live the whole span. A day warped is a day of food eaten, a day of charge drawn and a day of antimatter containment paid for, all spent in one step.
• No sunlight passes the wall. Solar panels make nothing in there, however long you are inside. A ship that runs on panels comes out flat; an RTG-1 keeps making its trickle in there, because it never needed the sun.

And it buys you no speed. You arrive on the same orbit, travelling exactly as fast as that orbit travels at the point you arrive at. Nothing about the fuel a journey costs changes; what changes is how long you sit through it.

The three drives

Three parts. The Warp Coil is 4 m across and sold on tier 4 (Warp Theory), the probe's drive, reachable before anybody has been to Mars; the Ring and the Lattice are 8 m across on two tier 5 nodes. No drive comes before the mine that fuels it, because every microgram a drive burns is mined: the small mine is tier 3, a tier ahead of the Coil, and the wide mine shares tier 5 with the big drives. They differ in how big a bubble they close, how hot its wall runs, how long they will hold it and what that costs.

The bubble is what each drive is built around, and it is a real size: thirty metres for a probe and what it carries, forty-five for a crewed ship with its radiators out and a hold on the back, a hundred and seventeen for a station — wider than the tallest rocket the third Launch Pad will ever release in one piece. Your ship has to fit inside it.

The wall's temperature is the catch, and it is why a bigger drive is not simply a better one. See Heat picks your drive below.

What a jump costs

Antimatter, in two parts. There is a one-off charge to form the wall, and a trickle for every second skipped to hold it. The sheet spells both out before you commit: "8.94 μg to form the wall + 311 μg to hold it = 320 μg of 400 aboard".

The holding charge is the one that adds up, and the reactor that keeps the lights on inside the wall burns for the whole span too. A full AM-8 Antimatter Container holds 170 μg: with its plant counted, that is about 136 days of wall under a Coil with an AR-4, 34 days under a Ring with an AR-8, or 17 days under a Lattice. A probe's own AM-4 holds 50 μg, forty days of Coil. A Mars leg is seventy-six days, about 94 μg, so a Coil probe crosses to Mars on two AM-4s; the nearer giants take two to five full AM-8s; Pluto's thirteen-year fall about thirty-six.

None of it is bought. A container launches empty, and every microgram in it came out of a converter in orbit, from helium-3 dug on the Moon. The first warp is fuelled by the small mine: one MR-4 rig on the Moon's richest field and one AC-4 converter make the Mars leg's micrograms in about eleven and a half days of running. The first warp's fuel has the sums, and Warp a ship the route.

Gravity makes the ignition dearer. The charge to form the wall is multiplied by how strong gravity is where you light it, adding 18 % for every point on the gravity gauge your Antimatter Container already reads. In a 100 km parking orbit over Earth that is ×1.69. Two thousand kilometres up it has fallen to ×1.49, and far from any world it is ×1. The sheet says which: "Ignition is ×1.49 here: gravity. Raise the orbit and it falls toward ×1."

So raising your orbit before lighting a bubble is a real procedure, not a flourish. It is cheapest on both counts out where the gauge reads nothing: the ignition is at par and the container beside it is at its cheapest upkeep too.

The holding charge does not care where you are. Only the ignition does.

Your ship has to fit inside the bubble

The wall is not a picture. It is a sphere, centred on the drive itself, and when it closes it cuts whatever it passes through. Anything outside the wall at that moment is destroyed where it stands — and a part the wall runs through counts as outside, because the wall goes through it.

So a drive's bubble is the size of ship it can carry. A Warp Coil's 30 m reaches fifteen metres in every direction from the Coil; a Warp Ring's 45 m reaches twenty-two and a half. That is measured from the drive, not from the nose, which means the drive belongs in the middle of the ship, not at the tail. A Ring bolted under the engines of a thirty-metre stack cannot reach the capsule at the top, and the first time you form a bubble the capsule — and everyone in it — is gone.

The hangar draws the circle. Tap a warp drive on the build canvas and its bubble is drawn round it at its true size, with anything that falls outside outlined in the same colour. Under the mass the readout says which drive and how much is outside it: Warp bubble: 45 m / 2 parts outside it. Move the drive until the circle takes the whole ship, and there is nothing left to go wrong.

In flight the warp sheet says it once more before you commit, in red with the loads: 2 parts are outside the wall and will be destroyed. That line is there because a ship changes shape in orbit — a docking, a dropped stage — and the bubble that fitted on the pad may not fit now.

Heat picks your drive

Inside a bubble the sky is the wall, and a radiator only sheds into a sky colder than the fluid in its pipes. A Warp Coil's wall at 350 K is cold enough for water pipes. A Warp Ring's at 600 K is not, so a Ring ship wants potassium. A Warp Lattice's at 800 K leaves only sodium.

The game checks this before it forms anything. Ask for a bubble your ship cannot shed its heat into and it refuses, naming the figures: "The wall runs at 600 K: this ship can only shed 0 kW of its 78 kW there." Reactors and heat has the whole ladder and how many fins each combination wants.

This only applies inside a bubble. Out in the open the sky is as cold as space, and every radiator works at its full rate whatever fluid is in it.

Nothing happens until the sheet has said what will

A warp lives its whole span in one step. There is no watching it and no aborting halfway: a crew that would have starved at hour twenty of a twenty-four hour jump is simply lost when the wall opens. So the Warp sheet puts everything on screen first.

It forecasts every load aboard — food, charge, antimatter — as it will stand when the bubble opens, and anything that reaches zero on the way is written in red with how long it lasts: Electricity — runs out after 101 min. That red line is the whole reason the sheet exists. Shorten the span, or carry more, or fit a reactor that does not need the Sun.

The bill and a reactor share the antimatter. The wall's bill leaves your containers the moment it closes, and an antimatter reactor aboard burns what is left for the whole span. The forecast counts both, so the Antimatter row is what the two leave between them. Each can fit on its own and the two together still not: then the row is red, the reactor goes cold the day the antimatter runs out, the batteries run down after it, and the Electricity row is red too. Shorten the span, or carry more antimatter.

The forecast is the jump itself, worked out on the sheet before you commit: what the wall cuts away goes first, with anyone sitting in it, then the bill, then the whole span. In sandbox it also says what the span destroys, in red above the loads: an antimatter container whose upkeep the batteries stop paying lets go inside the wall, AM-8 Antimatter Container will be destroyed in the span. In the shared world such a container leaks inside the wall instead, and if it still holds antimatter with no power when the bubble opens, it goes up a minute later unless you vent it or get the power back; the red Electricity row is your warning there. A load the cut or the bill takes all of reads gone when the wall closes. On a big ship the sheet can take a moment to work the span out; until it has, the line above the button reads Working out the span… and the button waits.

When it refuses, and why

The game checks the whole jump before anything happens, and says which rule stopped it in its own words.

That last rule is the one that surprises people: because the rest of the world holds still, a ship you left in the same orbit is a fixed obstacle for the whole jump. Anything within 250 m of your path counts.

What it is for

Waiting. An apoapsis four days out, a phasing orbit that has to go round eleven times, a transfer that spends three months coasting with nothing to do: those are hours of real time you would otherwise sit through, and the Warp sheet's To apoapsis and To periapsis buttons set the span for the two you want most.

What it is not for is getting anywhere sooner than the fuel allows. The orbit you leave on is the orbit you arrive on. Plan the burn first; warp to where you meant to make it.

A maneuver node you have placed stays on the point of the orbit where you put it, burn and all. A node fifty days out is twenty days out after a thirty-day warp, and warping the remaining twenty days puts you right on it. A node the warp carries you past stays behind you as a passed node, just as one ordinary time warp runs past would.

In sandbox

Warping works in sandbox as it does in the shared world, and the same rules refuse it. Sandbox also has ordinary time warp, which speeds the whole world up; a warp drive does not, and in the shared world it is the only way to skip a coast at all.