Summary
In 1986 Science Realm was followed by the Have Region program, to complement the ongoing air-breathing work in the NASP program. Main goal was to further develop structures and TPS to reduce risk. Under the program three prototype lightweight structures in scales from 40 to 100% were fabricated from exotic metals, primarily titanium and high-temperature superalloys, to evaluate near-term flight readiness. In tests the Boeing concept was validated and the built but untested Lockheed and McDonnell Douglas designs were classified as partial successes. The test articles were within 3% of required SSTO design weights. Regardless in 1988 it was concluded that the materials developed for NASP were more promising. Total cost of Have Region was around $40 million.
Sources
http://www.secretprojects.co.uk/forum/index.php/topic,315.0/all.html