Air launch from scram jet?
Seems that good progress is being made in scramjet engine design
scramjet engine test
For you back of the envelop rocket scientists, what efficienciencies can be had for an air launch from a scramjet? My imagination has me thinking about a base craft acting as a stage 1 going mach 9 making the edge of space before deploying a (thin) air launched rocket. Has anyone predicted what cost savings might be had for such a configuration, and what payloads per cost could be orbited?