About this game

Orbital Dash is the hardest game on Physics Arcade and the most faithful to the idea it is built on. Each planet is an inverse-square gravity well: halve your distance and the pull quadruples. You start on a circular orbit with the exact velocity that balance requires, and almost every input you make afterwards breaks it.

The counter-intuitive part is what thrust actually does. Burning along your direction of travel does not move you forward — it raises the far side of the orbit, and you arrive there later. Burning against your motion lowers the near side, which is how you avoid clipping a surface. Playing this well means thinking about the whole orbit, not about the next second.

How to play

  1. The probe begins on a stable circular orbit around the first planet. Do nothing and it will stay there.
  2. Rotate with the left and right arrows to choose a heading, then hold Up to burn.
  3. Collect every ring in the system. Rings also top up your fuel.
  4. Do not touch a planet surface, and do not leave the screen — both end the run.
  5. Clear six systems to finish.

Physics mechanics

Here is what the simulation is actually doing while you play.

Inverse-square attraction

Each well pulls with a force proportional to 1/r². At half the distance the pull is four times stronger, which is why a close pass accelerates you so violently and why slow approaches are more dangerous than fast ones.

Circular orbit velocity

The probe's starting speed is computed as the square root of the well strength divided by the orbital radius — the standard circular-orbit relationship. That is why it holds its path with no input from you.

Prograde and retrograde burns

Thrusting along your velocity raises the opposite side of the orbit; thrusting against it lowers the opposite side. Short burns near a planet change the orbit far more than long burns far away, because that is where you are moving fastest.

Escape velocity

Add enough energy and the orbit stops being closed. Leaving the play area means you exceeded escape velocity, which is a failure state rather than a boundary collision.

Objective

Collect every ring in a system without crashing into a planet or escaping the system. Six systems complete the run.

Scoring

  • Each ring is worth 200 points and restores 16 units of fuel.
  • Clearing a system awards 500 points plus 12 points per unit of fuel remaining.
  • There is no time bonus — patience is free.

Scores, favourites and play history are stored in your own browser using localStorage. There is no account, no leaderboard and no server: clearing your browser data clears them, and they do not follow you to another device.

Tips

  1. Let the orbit work. The fastest route to a ring is often no input at all. Watch a full orbit before you touch anything.
  2. Burn at periapsis. A burn made at the closest point of your orbit changes the far side the most, for the least fuel. This is the single biggest efficiency gain available.
  3. Retrograde saves you. If you are spiralling towards a surface, point against your velocity vector — the dashed yellow line — and burn.
  4. Watch the influence rings. The faint circles around each planet mark where its pull becomes significant. Crossing one means your trajectory is about to bend.
  5. Fuel is a hard limit. With no fuel you cannot change orbit at all. If you are below 25 units, make the next ring your only priority.

Difficulty

Expert. This game asks you to think in orbits rather than in directions, which is genuinely unfamiliar even for experienced arcade players. Expect several runs before system two clicks. Once it does, the difficulty curve flattens sharply because the same reasoning works everywhere.

Features

  • Inverse-square gravity wells with visible influence rings
  • Six systems with one to four planets each
  • Probe starts on a genuine circular orbit, not stationary
  • Fuel that only refills by collecting rings
  • Live velocity vector and orbital trail

How accurate is this?

Physics Arcade games use simplified, tuned physics built for playability. They are not scientific simulations: forces, masses and timings are chosen because they feel good at 60 frames per second, not because they match measured values. Where a game departs from real-world behaviour in a way that matters, the game page says so.

Orbital Dash – FAQ

Why does thrusting forward not speed me up?

It does add energy, but in an orbit that energy goes into raising the opposite side of your path rather than into immediate forward motion. This is a real orbital-mechanics result, simplified but not faked.

How do I slow down?

Point against the yellow velocity vector and burn. There is no drag in space, so a counter-burn is the only brake.

What happens if I leave the screen?

The run ends — you exceeded escape velocity. The play area boundary stands in for the edge of the system.

Is the starting orbit always stable?

Yes. The probe is given exactly the circular-orbit velocity for its starting radius, so with no input it will hold that orbit indefinitely.