https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation It's also about gravity, since gravity is w

https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation It's also about gravity, since gravity is what you are fighting against.