Soft Landing

Splashery stretches a drumhead over this Splash's outline, twelve inches across, and finds the ways it can ring. Its lowest is 545.4 Hz, 72 cents sharp of C5, the nearest tine on the comb. The next fifteen are its overtones, and each one draws its own figure: sand gathers on the lines that stay still.

Tap or press Space to play. ← → tip the lander, ↑ or Space fires. Land slowly and upright on level ground.

The ground here is real. On the Moon it comes from the laser altimeter and camera of NASA's Lunar Reconnaissance Orbiter (the CGI Moon Kit): Tycho crater, Copernicus crater and the Sea of Tranquility, where Apollo 11 landed. On Mars it comes from Mars Global Surveyor's laser altimeter: Gale crater, Jezero crater, Valles Marineris and Olympus Mons, colored by height. Heights are drawn taller than life so the shapes read; the site's card says how much.

Gravity pulls the lander down and the engine pushes it the way it points. Touch down slowly, upright and on level ground (the green lights mark flat spots) to score, with more for fuel left; land badly and it breaks apart. 2D is a true slice through the ground; the 3D button lifts the camera to show the whole patch of terrain around the slice, and the flight goes on.

This link opens it in the Playground. To put it on your own page, add the element and one script tag. Every option.