Rocket Game

Rocket Game is a build-and-launch game: you put a rocket together from parts in a simple hangar, then fly it up through the atmosphere and see how high and how fast it gets. Stack fuel tanks on an engine, add fins and a nose cone, split it into stages, and try to reach space. You can play Rocket Game online free in your browser with no download, on a keyboard, a mouse or a phone’s touch screen.

How to play

Every flight has two parts: building in the hangar and flying the launch.

• Build: tap a part to add it to the stack. It goes in below the selected part, or at the bottom. Nose cones and the satellite always sit on top. Tap a part on the rocket to select, move or remove it.
• Check the numbers: the hangar shows each stage’s delta-v and its thrust-to-weight ratio (TWR). A first stage under 1.0 TWR will not leave the pad.
• Check stability: the yellow marker is the center of mass and the blue ring is the center of pressure. The rocket is stable when the blue ring sits below the yellow marker. Fins low on the rocket pull it down; fins near the top do not help.
• Launch: press Launch (or Enter), then STAGE (or Space) to light the engine. Steer with Left and Right (A and D) or the Steer buttons, and throttle with Up and Down (W and S).
• Stage: a decoupler splits the rocket into stages. Pressing STAGE drops the boosters first, then the empty lower stage, and lights the next engine.

A flight ends when the rocket comes back down, breaks apart, or you press End flight. Use Warp (or T) to speed up long coasts, and P or Esc to pause.

The physics

The flight model is simplified but follows real rules. Engines burn fuel at a fixed rate, so the rocket gets lighter and accelerates harder as the tanks empty. That is why the hangar’s delta-v figure uses the Tsiolkovsky rocket equation: delta-v equals the engine’s specific impulse (Isp) times standard gravity times the natural log of full mass over empty mass.

• Air: air density falls off with height, so drag is strongest low down and fades away high up. Nose cones cut drag, and the ogive nose cuts it most.
• Engines: each engine has a sea-level Isp and a higher vacuum Isp. The Wisp Vac engine is weak in thick air but the most efficient once you are high up, so it suits upper stages.
• Stability: if the center of pressure is ahead of the center of mass, the air pushes the nose sideways, and a small wobble grows until the rocket tumbles.

Missions and coins

Every flight counts toward all five missions:

• 10 km and 50 km: reach those altitudes.
• Space: cross 100 km, the Kármán line, a common way to mark where space begins.
• Orbit-lite: stay above 100 km for 60 seconds while moving sideways at 2,000 m/s or more.
• Satellite: carry the satellite and release it above 120 km at 2,000 m/s or more sideways.

Each mission pays a one-time reward (50, 100, 200, 400 and 600 coins), and every flight also pays 1 coin per kilometer of peak altitude. Coins unlock bigger tanks, engines, boosters and the satellite. Coins, missions, your best altitude and your last design are saved in your browser.

Tips

• Fins go at the bottom. If the hangar says UNSTABLE, add fins below the lowest tank.
• More tanks is not always better. Extra fuel adds delta-v but lowers TWR. Below about 1.2, gravity eats much of your fuel.
• Stage to shed weight. Dropping an empty tank and a heavy engine makes the upper stage far more effective.
• Turn early and gently. Go straight up for the first kilometer, then lean over a little at a time. By 100 km you want to be pointing nearly sideways to build speed for orbit-lite.

FAQ

Is Rocket Game free?

Yes. It is free with no account and nothing to install.

Does it work on phones and Chromebooks?

Yes. On a phone, tap parts to build, then use the on-screen Steer, Throttle and STAGE buttons. Touching the game won’t scroll the page. On a Chromebook or laptop, use the keyboard in any modern browser.

Why did my rocket break apart?

It tumbled. Usually the center of pressure was ahead of the center of mass (add fins low down), or you steered too far from your direction of travel while the air was still thick.

Want a softer touchdown afterwards? Try Moon Lander and set a lander down on the moon, or fly through the clouds in Plane Pilot.