A mass driver is an electromagnetic catapult which uses a linear motor ti accelerate and catapult payloads and craft at very high speeds. Often, mass-drivers double as an orbital defense system for launching military payloads or interception craft into space. They are a cheaper alternative to the use of rocketry or high grade engines for moving into space and are very common for unmanned ships or those operating on a budget - and the acceleration of mass-drivers often comes with several health-hazards for living travellers caused by the high gravitational forces experienced. These acceleration forces must be prepared for via special means in order to prevent injury.