发射环是一个设想中的非火箭航天发射装置。通过利用一个架在距地面80公里，长为2000公里的高架环路上的磁悬浮带，把负载发射到某个轨道上。整个带子在将负载抛射出地面后，向下，并反向向来的方向运动直到最初的发射端，这样构成一个环形回路。

A launch loop or Lofstrom loop is a proposed system for launching objects into space orbit using a moving cable-like system situated inside a sheath attached to the Earth at two ends and suspended above the atmosphere in the middle. The design concept was published by Keith Lofstrom and describes an active structure maglev cable transport system that would be around 2,000 km (1,240 mi) long and maintained at an altitude of up to 80 km (50 mi). A launch loop would be held up at this altitude by the momentum of a belt that circulates around the structure. This circulation, in effect, transfers the weight of the structure onto a pair of magnetic bearings, one at each end, which support it.