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That is the game. Every command travels from Earth to the rover at the speed of light, so it lands seconds after you send it. On Mars that is about 4 seconds on screen, standing for the real 11 minutes 22 seconds. The top of the screen shows the real delay and the time factor for every drive.

It is your rover's future: where it will be when a command you send now lands. Drag left or right to bend it round hazards, and brake when the cyan stop marker sits inside the science ring.

Drag left or right to steer. Tap to brake. Tap again right after the first tap and that brake lands as a hard stop, which stops the rover in a much shorter distance. Each rover brakes and steers differently: the hangar shows its stopping distances.

Stop inside the science ring to finish a mission. Stop within 2 m of its centre for one star, within 1 m for two and within 30 cm for three. If you miss, you run the same course again: every mission is the same ground every time.

The Moon and Mars are open from the start. Each world after that opens when you have enough stars on the world before it. Europa, Titan and Enceladus also need range: one, three and seven light-days. A world stays open once you have opened it.

Range is the total real light time crossed by your commands that landed. One brake on Mars adds about 11 minutes of light. Rovers unlock at range milestones: SENTINEL at 6 light-hours, STRIDER at one light-day, HORIZON at one light-week, and the premium rovers from one light-month to two light-years. See the fleet.

Runs helped by a premium rover's ability (autopilot, hop, laser or orbital relay) never reach the leaderboards, so the boards only compare hands on the wheel. You also need to be signed in to Game Center.

Lightlag uses Apple Game Center for its leaderboards (range, stars and lifetime science) and 31 achievements. If you are signed in to Game Center on your iPhone, scores and achievements are sent to it as you play. You can also sign in from Settings in the game.

Open Settings in the game and use Daily reminder. It is a local notification at 14:00 UTC when a new drive is live, set on your iPhone itself. If iOS says notifications are off for Lightlag, turn them on in the iOS Settings app under Notifications.

Yes. Settings in the game has switches for sound effects, music, haptics and Reduce motion, which calms the camera and screen effects.

On your iPhone. Lightlag has no account and no login, and it does not send your progress to us. Because of that, progress does not move between devices, and deleting the app deletes its progress too.

Open Settings in the game, choose Reset progress and tap again to confirm. This erases stars, range and missions on this device. Game Center achievements you already earned stay with your Game Center profile.

See Delete your data. In short: reset progress or delete the app, and manage Game Center data in iOS Settings.

iPhone with iOS 16 or later, held in portrait. Lightlag is coming soon; it is in testing now. To ask for a place in the beta, email us with the subject "Lightlag beta".

Email krishcdbry@gmail.com with:

• your iPhone model and iOS version,
• the world, mission number and rover,
• what you did, what you expected and what happened instead,
• a screenshot or screen recording if you can.