1. Reddit user Ulysse Carion made this subway map based on our solar system.
2. What are these calculations, anyway?
In the simplest terms, they’re the changes in velocity a spacecraft can produce, or delta-v (or Δv, if you want to look super cool). That’s what the numbers on the subway lines represent.
3. Flying in space means moving from orbit to orbit.
And to do so, you need to change your velocity.