The National Aeronautics and Space Administration sponsored a joint High-Sp
eed Research Programme with United States airframe and propulsion companies
to provide the critical high-risk technologies for a Mach 2-4, 300 passeng
er civil transport. Laboratory and medium-scale tests provided promising re
sults in meeting both the environmental and economic goals for a future Hig
h-Speed Civil Transport. However, before the technologies were integrated a
t large and full scale, the programme was cancelled because of global econo
mic concerns of the US transport industry.