Educational orbit and gravitation simulator for high school, college and beginning university physics and astronomy. Input mass, radius, coordinates and velocity components of 2 to 10 bodies manually or by dragging and dropping predefined bodies. Then watch how the orbits evolve under the mutual gravitaional attractions. Save and print the simulation.

Great for 'lab exercises' in gravitational physics or for verifying numerical answers to textbook problems. Includes 40 introductory to advanced premade simulations with activities page in html-format. Simulations include elliptical satellite orbits, Kepler's laws, double star, geocentric and heliocentric world view, Lagrange points, gravity assist, Hohmann orbit, extrasolar planet, inner solar system. Uses actual pictures of planets.

Plot orbits in a plane or in 3D. View time, distances, speeds, accelerations, energies and acceleration vectors as they change. Adjust the simulation speed to fit your computer. Zoom and change parameters during the simulation. Run up to four simultaneous simulations.

Tutorial and context-sensitive help included.