Non-rocket spacelaunch

Non-rocket spacelaunch refers to concepts for launch into space where some or all of the needed speed and altitude are provided by something other than rockets, or by other than expendable rockets. A number of alternatives to expendable rockets have been proposed. In some systems such as a combination launch system, skyhook, rocket sled launch, rockoon, or air launch, a rocket would be part, but only part of the system used to reach orbit. Non-rocket spacelaunch refers to concepts for launch into space where some or all of the needed speed and altitude are provided by something other than rockets, or by other than expendable rockets. A number of alternatives to expendable rockets have been proposed. In some systems such as a combination launch system, skyhook, rocket sled launch, rockoon, or air launch, a rocket would be part, but only part of the system used to reach orbit. Present-day launch costs are very high – $2,500 to $25,000 per kilogram from Earth to low Earth orbit (LEO). As a result, launch costs are a large percentage of the cost of all space endeavors. If launch can be made cheaper, the total cost of space missions will be reduced. Due to the exponential nature of the rocket equation, providing even a small amount of the velocity to LEO by other means has the potential of greatly reducing the cost of getting to orbit. Launch costs in the hundreds of dollars per kilogram would make possible many proposed large-scale space projects such as space colonization, space-based solar power and terraforming Mars.