This article is about rocket launches assisted by non-rocket powered guideways. For rocket-powered railways, see rocket sled. A rocket sled launch, also known as "ground based launch assist", "catapult launch assist", and "sky ramp launch", is a proposed method for launching space vehicles. With this concept the launch vehicle is supported by an eastward pointing rail or maglev track that goes up the side of a mountain while an externally applied force is used to accelerate the launch vehicle to a given velocity. Using an externally applied force for the initial acceleration reduces the propellant the launch vehicle needs to carry to reach orbit. This allows the launch vehicle to carry a larger payload and reduces the cost of getting to orbit. When the amount of velocity added to the launc