USAF program of the 1980's that reached the test hardware stage and was leading to a single-stage-to-orbit, rocket-powered, winged manned vehicle. Halted in favour of the X-30 National Aerospace Plane.

The Air Force's classified Trans-Atmospheric Vehicle development of the 1980's originated with the AMSC (Advanced Manned Spaceflight Capability) program of 1978. This studied the utility of manned spacecraft for military purposes. Trade studies were made of the technical alternates (one or two stages, vertical or winged horizontal takeoff and landing). The technical data generated during the Isinglass program of the 1960's was used as a starting point. The initial findings were positive, and it led to the following technology programmes of the 1980's:

• Science Dawn, 1982 - Three in-depth preliminary designs were made by hand picked design teams. The vehicles would have used upgraded shuttle SSME engines. These would operate at 109% and 115% of nominal thrust, be modified for horizontal operation and be equipped with a two-position nozzle for higher specific impulse at high altitudes.
• Science Realm, 1984 - This phase resulted in design of a structural test article.
• Have Region, 1986 - This phase resulted in the actual manufacture and test of structural articles. Three structural concepts, were built. Two were considered partial successes, and one concept was considered completely validated. This used a stainless steel hydrogen tank liner and demonstrated a propellant utilisation fraction of 0.88.