Non-rocket spacelaunch

Non-rocket spacelaunch refers to theoretical concepts for launch into space where much of the speed and altitude needed to achieve orbit is provided by a propulsion technique that is not subject to the limits of the rocket equation. Although all space launches to date have been rockets, a number of alternatives to rockets have been proposed. In some systems, such as a combination launch system, skyhook, rocket sled launch, rockoon, or air launch, a portion of the total delta-v may be provided, either directly or indirectly, by using rocket propulsion. 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. In this usage, the term "static" is intended to convey the understanding that the structural portion of the system has no internal moving parts. A space tower is a tower that would reach outer space. To avoid an immediate need for a vehicle launched at orbital velocity to raise its perigee, a tower would have to extend above the edge of space (above the 100 km Kármán line), but a far lower tower height could reduce atmospheric drag losses during ascent. If the tower went all the way to geosynchronous orbit at approximately , objects released at such height could then drift away with minimal power and would be in a circular orbit. The concept of a structure reaching to geosynchronous orbit was first conceived by Konstantin Tsiolkovsky. The original concept envisioned by Tsiolkovsky was a compression structure.