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PolskiEarth Orbit Simulator (2D)
A 2D Kepler-orbit lab: adjust perigee altitude, eccentricity, plane inclination and time warp to trace a satellite's real elliptical path around Earth, with live altitude, speed and period readouts driven by the vis-viva equation.
This 2D companion solves the same orbital mechanics as the 3D version on a flat canvas: perigee altitude and eccentricity set a focus-centered ellipse with Earth fixed at one focus, Kepler's equation is solved by Newton–Raphson every frame to place the satellite, and the vis-viva equation gives its instantaneous speed — so altitude, velocity and period all move together exactly as real orbital mechanics predicts when you drag a slider.
2D Kepler-orbit lab: perigee altitude, eccentricity, inclination tilt and time warp drive a satellite along a real focus-centered ellipse, with altitude, speed and period computed from Kepler's equation and the vis-viva equation each frame.
2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install
Kepler's second law: a line from Earth to the satellite sweeps equal areas in equal times, so the satellite must move faster at perigee (closest point) and slower at apogee (farthest point) to keep that area rate constant — the vis-viva equation in this sim reproduces exactly that.
It visually squashes the orbit ellipse vertically to represent viewing an inclined orbital plane from outside it, the same foreshortening a real inclined orbit shows when projected onto a flat view — the underlying ellipse geometry (semi-major axis, eccentricity) is unchanged.
From Kepler's third law, T = 2π√(a³/μ), where a is the semi-major axis and μ = GM_Earth = 398,600.4 km³/s². Low orbits like the ISS take about 93 minutes; geostationary orbit takes 24 hours.