Tutorial

Walking a mission

A mission is a walk across a city at the true scale of the solar system. You start at something round and real — a fountain, a dome, a sculpture — and that object's actual size decides where every planet lands. Then you go and find them.

Before you set off

What you need:

• A phone with a browser. There's no app and no account.
• Your Sun card or a mission postcard. Either one works, and either one works in every city, forever.
• Comfortable shoes. A typical walk is a few miles; a large one is a proper day out. The mission page tells you before you commit.

What you don't need: a signal at every stop (the walk keeps working offline once a page is open), perfect GPS, or the ability to reach every single planet. All three have escape hatches built in.

The card is the ruler. When a planet appears in front of you, its size is measured against the printed border on your card or postcard back. That's why one card works everywhere and why the scale is real rather than approximate. You can walk a mission without a card — you'll get the route, the stops and the directions — but the planets need it.

1 · Pick a mission

Two ways in, depending on how you arrived.

You have a postcard

Scan the code on the front. That's the one code tied to a specific walk, and it opens that mission's page directly. Scroll it before you decide — this is the page that tells you what you're signing up for:

• A map of the whole route, drawn at true scale, with every planet's orbit ring.
• Total distance and a rough time estimate.
• Every stop in order, with the landmark it's at and any hint about finding the exact spot.
• Tags for the shape of the walk — whether it's free, transit-friendly, that sort of thing.
• A waypoints download (KML), if you'd rather plan the far legs in your own map app first.

Read the outer stops especially. At real scale Neptune can be a genuine expedition, and it's better to know that at the kitchen table than at Saturn.

You don't have a postcard

Go to Explore — from the homepage, the footer, or the Explore code on the back of the wallet card. It opens on a map of published walks. Allow location and it frames the ones near you; deny it and you'll get a sensible wide view you can pan yourself. Nothing auto-selects a walk for you.

Tap a pin to see what's there. One pin can hold several walks if they share the same Sun — a good landmark often gets more than one route drawn from it, heading in different directions. Pick the one you like and hit Show mission details →, which takes you to the same mission page a postcard would have opened.

You can also walk something that was never published: a walk you built yourself in the planner, or one a friend sent you as a link. Those live on your device only, and from here on they behave exactly like a published mission — your card finds them in the street the same way.

2 · Get to the Sun

On the mission page, tap Walk this mission →. Two things happen:

1. The walk is activated on this device. That's what lets the GO code know what to do later — from now on, scanning GO means "where am I in this walk?"
2. You get pointed at the Sun. Its name, its real size, how far away you are, and buttons that hand off to Google Maps or Apple Maps for walking, transit or driving directions.

We deliberately don't try to route you to the walk. That leg is usually a train or a drive from home, and your map app does it far better than we could. Our job starts when you get there.

Already standing at the Sun? The page checks your location when it loads and skips this step entirely, dropping you straight into the arrival card below. Nothing to do.

Already on another walk? You'll get a confirmation before switching, naming how far into the old one you were. Switching never destroys anything — the old walk stays saved exactly where you left it, and you can switch back.

3 · Arrive at the Sun

Stand at the Sun object and scan the GO code. This is the moment the walk actually begins, and it's the one stop you can't skip — everything else is measured from it.

You get the arrival card, which says three things:

• How big your Sun is. "This 6 ft sphere is your Sun."
• What that costs you. The farthest stop on the walk, by name and distance, and the reminder that nothing was invented to make it fit.
• The scale ratio, written out — something like 1 : 227,000,000.

Below that: your first stop, how far it is, and the button that starts everything — Begin the walk →. Directions to that first stop are folded away under it, because the inner planets are usually close enough that you can just look.

This screen is worth actually reading. It's the only place the scale is stated in concrete terms, and it's the thing that turns "a walk with QR codes" into "I am standing on the Sun and Neptune is nine miles that way."

4 · Walking between stops

After Begin the walk →, and after every stop from then on, you're handed the next one. Depending on what your phone can tell us you'll get either live walking directions with a map, or a next-stop card with:

• The planet's name and the landmark it's at.
• How far away it is.
• A hint for finding the exact spot, if the walk's author wrote one.
• A transit tip, if getting there is more than a stroll.
• Buttons out to Google or Apple Maps.

And two escape hatches, which are there for good reasons:

“I'm at [landmark] now →”

City GPS is routinely thirty to a hundred metres off — tall buildings, tunnels, a phone that's been in your pocket. If you're standing at the right landmark and the app disagrees, tap this. It credits the stop and takes you to the planet. This is a scavenger hunt, not an anti-cheat system; we'd rather trust you.

“Can't get to [planet]? Skip this stop”

At real scale an outer planet can be across a river, behind a closed gate, or simply two hours away. Skipping moves the walk on. A skipped stop is not counted as found — your walk will honestly read "6 of 8 found, 2 skipped" — and you can always come back and pick it up later.

5 · Standing at a planet

Arriving at a stop is the point of the whole thing, so it gets its own screen rather than throwing you straight into a camera. You get there by scanning GO within range of the stop, or by tapping "I'm here", or by the walking map noticing you've arrived — all three mean the same thing and land in the same place.

The stop page shows, top to bottom:

• Which planet you're at, the landmark's name, and a ✓ Found badge — the credit stated out loud rather than happening silently.
• A “Not the stop I'm at →” link, in case it guessed wrong. One tap un-does the credit and opens the full list so you can pick the right one. This matters at small-Sun walks, where Mercury and Venus can be close enough to share a GPS circle.
• A photo of the spot, so you can check yourself against it. Some stops also have a 360° view you can drag around — tap Look around.
• A note about what to look for when you're standing there.
• “See [planet] at true scale →” — the AR button. It's above the reading material on purpose; if you came for the planet, you shouldn't have to scroll past a café recommendation to get it.
• Something to read about the place, and nearby things worth a detour.
• “Head to [next planet] →” at the bottom, with the distance, plus any note the author left about getting there.

Nothing on this page is a timer. You can open it, wander off, come back, close the tab, take a call — it changes nothing. It exists so the walk has a beat where you stop moving and look at where you are. That's the part people remember, and it's why the stops are at real places rather than empty corners.

6 · Seeing it at true scale

Tap the AR button and the camera opens. Hold up your wallet card or the back of your postcard — the side with the busy printed border — and point the camera at it. The planet appears, sized against that border, against the real street behind it.

Getting a good result:

• Fill a decent part of the frame with the border. Too far away and there isn't enough detail to lock on.
• Any orientation is fine. Sideways, upside down, at an angle — it tracks.
• Even light helps. Deep shade and direct glare are both harder than an overcast afternoon.
• Prop it up. A card on a bench, a wall, or a friend's hand frees you to line the shot up properly.
• If the card leaves the frame, the planet stays where it was rather than vanishing, so a brief wobble doesn't cost you the shot. Bring the card back and it re-anchors.

Then take the photo. Bring people into it — the scale reads far better with something human next to it, and a group photo with Jupiter is the single best thing this produces.

When you're done, Next planet → in the camera view drops you back on the stop page you were standing on, not off down the road.

Two useful facts. The size follows whichever piece is in front of the camera, not the code you scanned — so scanning a postcard's GO code and then holding up your wallet card still gives you the right size. And if the AR doesn't work out at all, you're not out of luck: photograph the scene with the card in shot and add the planet afterwards in the photo editor.

7 · Onward, and outward

Now it repeats: Head to [next planet] →, walk, arrive, look, planet, move on. Mercury, Venus, Earth, Mars — and then the gap.

The jump to Jupiter is where a solar system walk stops being a stroll and starts being the thing you tell people about. The four inner planets are usually a few blocks apart. Jupiter is a different neighbourhood, Saturn a different part of town, and Neptune can be a bus ride. That gap is not a design flaw we failed to smooth out — it is the single most accurate thing about the whole product, and feeling it in your legs is the point.

So, practically:

• Public transport is fine. Nobody is checking. Many walks have transit tips written into the outer stops for exactly this.
• You can stop and come back another day. Progress is saved on your phone. Scan GO whenever you pick it up again and it puts you back where you were.
• You can do the stops out of order. The app points you at the next unfound one, but the full stop list lets you credit any of them, whenever you get there.
• You can skip the ones that aren't worth it. A finished-with-skips walk is an honest result, not a failure.

8 · Finishing

At the last stop, the onward button reads Finish the walk → instead of naming another planet. Tap it and you get the finish screen:

• Planets found, out of the total.
• Miles on foot — the actual route you walked.
• How much solar system you crossed — that same distance multiplied back up by the walk's own scale. Hundreds of millions of miles, and it's the real number.

Then a share button (your phone's own share sheet, which is where Instagram, Threads and Messages live), a link to the mission's postcard if there is one, and three ways out:

• Walk this again — clears this walk's progress and starts you back at the Sun. It asks first.
• See your route — the map of everywhere you went.
• Find another walk — back to Explore.

There's also a quiet Finish and clear this mission at the bottom. It keeps your record but puts the walk down, so the next time you scan your card in a new city you get offered that city's walk instead of being told you've already finished this one.

Good to know

One walk at a time

Your card is on exactly one active walk. Starting another asks first and never destroys the old one — every walk you've ever started keeps its own progress, and you can switch between them freely from the help page.

Progress lives on your phone

Not on our servers — there's nothing to log into. That means it's private, it works offline, and it also means it's tied to this browser on this phone. Switching devices, using private browsing, or clearing your browser's site data will lose it. There's more on this, and on what to do about it, in getting unstuck.

The Sun is a step, not a planet

Visiting it starts the walk but doesn't count toward your planet total. A walk with eight planets finishes when you've found eight planets.

Nothing here is timed or scored

There's no leaderboard, no streak, and no way to fail. Take three hours or three weekends.