Can it just soar into orbit from 100,000 feet if it has enough inertia from the powered phase of the flight?
Interesting. Thanks for the info. Love stuff like that, but have little real knowledge of it.
Gotta remember to make a reservation at a Holiday Inn Express. I’ve got several areas of expertise that need honing.
No ... but it takes a lot less rocket to go from 100kft to orbit than it does to go from 0ft to orbit. So the idea is to reach some desired altitude with jet engines, then light the rockets. The 'desired altitude' is usually more like 50kft, using turbojet or turbofan engines. A higher altitude could possibly be reached using something like the SR-71's combination turbojet/ramjet engines.
The USAF/NASA X-15 and Burt Rutan's Spaceship One used this technique to achieve sub-orbital spaceflight. You'd need something bigger to make orbit, but it could be done.
Come to think of it, Orbital Sciences Corp’s “Pegasus” rocket uses this technique to put small satellites in Low Earth Orbit. Their original launch platform was a B-52; I believe they’re now using an L-1011.