SUSTAIN, or Small Unit Space Transport and Insertion, was first proposed in 2002 by the US Marine Corps. The idea is simple. Deploy Marines anywhere in the world within two hours by first sending them into space and then dropping them back down. Project Hot Eagle began developing the suborbital spacecraft necessary for the operation.
It would use a craft that would launch from a suborbital trajectory in two stages, first launching into space, then ceasing orbit in the proper location and lowering back down. The only problem is extraction, which would have to be done in a different way because the aircraft would have to be launched on a special runway.
Future possibilities for this technology are numerous, such as launching an entire army into space before releasing them all at once in an enemy territory. Sound interesting? Tell us your thoughts!