Space
Orbits, distance, and the mechanics of going anywhere.
How does a rocket fly to the International Space Station?
Getting to orbit is not the hard part. The hard part is arriving where the station will be, at the moment it gets there, moving at the same speed.
How a rocket gets into orbit
Height gets a spacecraft above the air. What keeps it there is sideways speed, and building that is most of what a launch is doing.
The solar system, to scale
Explore the Sun, eight planets, thirteen moons and four spacecraft, with sizes and distances shown on the same scale.
Why is it hard to fly above the solar system?
The planets orbit the Sun in roughly the same plane. Sending a spacecraft steeply out of that plane takes a large change in motion, because it starts with Earth’s orbital speed.
Trajectories to other planets
Reaching another planet means planning for where it will be when the spacecraft arrives. Explore how the departure date changes the journey.