Orbiter
You are on a space mission - to orbit the Earth in a precise amount of time. You only have a little fuel left and you must use it to get as close to the target time as you can!
The link address is: http://puzzling.caret.cam.ac.uk/pregame.php?game=14&PHPSESSID=65f1b591e2a1548e0f52d556373966ce
