Tutorial

Walking a mission

A mission is a walk across a city at the true scale of the solar system. You start at 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.
• 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.
• SUNSCREEN

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.

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.

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.

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.

3 · Arrive at the Sun

Stand at the Sun object and scan the GO code. This is the moment the walk actually begins.

You get the arrival card, which says three things:

• How big your Sun is. "This 6 ft sphere is your Sun."
• The overall mission size. The farthest stop on the walk, by name and distance.
• 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.

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.

5 · Standing at a planet

Arriving at a stop gets its own screen. You get there by scanning GO within range of the stop, or by tapping "I'm here".

The stop page shows, top to bottom:

• Which planet you're atand the landmark's name
• 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.
• A note about what to look for when you're standing there.
• “See [planet] at true scale →” the AR button.
• 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.

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...
• 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.

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.

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.

Jupiter is a different neighbourhood, Saturn a different part of town, and Neptune can be a bus ride.

If you need to split a walk up into a few days, do that, the point is to have fun!

• 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.

8 · Finishing

At the last stop, the onward button reads Finish the walk → 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.

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.