Editing Spacecraft propulsion (section)

===Launch-assist mechanisms===
{{Main|Space launch}}

There have been many ideas proposed for launch-assist mechanisms that have the potential of substantially reducing the cost of getting to orbit. Proposed [[non-rocket spacelaunch]] launch-assist mechanisms include:<ref>{{Cite web |date=1970-01-01 |title=Can We Get Into Space Without Big Rockets? |url=https://science.howstuffworks.com/can-get-into-space-without-big-rocket.htm |access-date=2024-04-28 |website=HowStuffWorks |language=en-us}}</ref><ref>{{Cite web |last=Bolonkin |first=Alexander |date=January 2011 |title=Review of new ideas, innovations of non- rocket propulsion systems for Space Launch and Flight (Part 2) |url=https://www.researchgate.net/publication/268426650 |access-date=April 28, 2024 |website=www.researchgate.net}}</ref>

*[[Skyhook (structure)|Skyhook]] (requires reusable suborbital launch vehicle, not feasible using presently available materials)
*[[Space elevator]] (tether from Earth's surface to geostationary orbit, cannot be built with existing materials)
*[[Launch loop]] (a very fast enclosed rotating loop about 80&nbsp;km tall)
*[[Space fountain]] (a very tall building held up by a stream of masses fired from its base)
*[[Orbital ring]] (a ring around Earth with spokes hanging down off bearings)
*[[Mass driver|Electromagnetic catapult]] ([[railgun]], [[coilgun]]) (an electric gun)
*[[Rocket sled launch]]
*[[Space gun]] ([[Project HARP]], [[ram accelerator]]) (a chemically powered gun)
*[[Beam-powered propulsion]] rockets and jets powered from the ground via a beam
*[[High-altitude platform]]s to assist initial stage