Table 1: Previously proposed launch assistance systems.

MethodReferences

High-altitude free-floating Montgolfier balloon[2]
Orbital electromagnetic catapult[3]
Laser ablation drive[46]
Space elevator[7, 8]
LEO rotovator[911, 13]
Spiral sling (slingatron)[1418]
Interplanetary rotating tethers[1929]
Rotating, tension supported ring[30]
Electromagnetic tether for raising orbit[3133]
Space fountain[34]
Ground-based linear accelerator (gun, catapult)[3639]
Subsonic launcher aircraft[40, 94]
Precooled air ramjet launcher aircraft[42, 43]
Supersonic launcher aircraft in general[41, 44]