Two small planets P₁ and P₂ orbit a star. A small capsule is launched from P₁. Try to place the capsule (green dot) in orbit around planet P₂. The initial velocity of the capsule is V₁ and launch angle θ₁ . You can use the impulse engines to control capsule speed. I wrote this about 20 years ago using C - it needs to be updated with more intuitive inputs and improved graphics.