Why are mass drivers/gauss cannons not used as an alternative to rockets in spaceflight?

Question

Is it due to energy demand or acceleration damaging the cargo/humans or something else?

In: 6

Answer 1

Apart from other concerns, reaching earth orbit from the surface requires acceleration of 3000 G kms. For example, you could accelerate at 1 G along a 3000 km long cannon, or accelerate at 3000 Gs with a 1 km long cannon. Sending most cargoes requires an impracticality large cannon.