Orbiteer

Build a rocket. Reach space. Circularize.

A build-and-launch-to-orbit sandbox with real Newtonian physics: point-mass gravity, exponential atmosphere with drag, Tsiolkovsky delta-v, staging, and live Keplerian orbit prediction — around a scaled planet with an orbiting moon.

How to play

Main menu → New Flight drops you in the Vehicle Assembly Building.

VAB (assembly)

• Click parts in the left palette to stack them: Command Pod, Nose Cone, Fuel Tanks, Liquid Engine, Solid Booster, Decoupler, Fins, Landing Legs.
• Reorder / remove parts in the right stack list. Decouplers split the stack into stages, fired bottom-up.
• The top bar shows live mass, thrust, TWR, and per-stage delta-v (Tsiolkovsky). You need TWR > 1 to lift off.
• Save designs for later. LAUNCH puts the craft on the pad.

Flight

Key	Action
Space	Ignite / next stage (drops spent stages)
Z / X	Full throttle / cut
Shift / Ctrl	Throttle up / down
W A S D	Pitch / yaw
Q / E	Roll
T	SAS attitude hold
M	Map view (orbit ellipse, Ap/Pe markers, moon)
Wheel	Camera zoom
R	Revert to launch
Esc	Pause

Reaching orbit

Launch straight up, then pitch over (W) around 20–40 altitude to start a gravity turn. Stage when a tank runs dry. Cut the engine when your projected apoapsis clears the atmosphere (100). Coast to apoapsis, point prograde, and burn until the periapsis also climbs above the atmosphere — the HUD flips to IN ORBIT and the map draws your closed ellipse.

The atmosphere ends at 100 units; both Ap and Pe above that is a stable orbit. Overburn and you'll escape; underburn and you fall back. The moon is out there at 2000 units, with its own gravity well, if you have the delta-v.

Best altitude and orbit progress persist with the world. Milestones toast as you hit them: Reached Space, Orbit Achieved, the moon's sphere of influence, and touchdown.