Throw-weight is like how far you can throw a ball. It's a fancy word that describes how much weight a rocket or missile can lift and throw into space. It's like when you throw a heavy ball, you can't throw it as far as a light ball. The same thing goes for rockets and missiles. They can only carry a certain amount of weight, and the more weight they have to carry, the less far they can throw it. The throw-weight of a rocket or missile is important because it helps scientists and engineers figure out how much weight they can send into space, and how far they can send it. Basically, it's the maximum payload a rocket can carry into space.