Hypersonics-A Periodic Quest

Current State of High Speed Propulsion: Gaps, Obstacles and Technological Challenges in Hypersonic Applications

“…69,71 The Hypersonic Research Engine/Hypersonic Ramjet Experiment (HRE) also flew as an experimental ramjet/scramjet on the modified X-15, the X-15A-2, but only as a dummy pod that inadvertently damaged the vehicle in flight. 6,67,70,72 Both Figs. 7a and 7b display the various air-breathing programs according to Tang and Chase.…”

“…7a and 7b display the various air-breathing programs according to Tang and Chase. 62,70 Note in Fig. 7b INTINSE scramjet flowpath (Fig.…”

Towards a rational strategy for the human settlement of space

“…In the long-term, many serious researchers believe that the lowest cost access to LEO will come from hypersonic vehicles exploiting plasma effects (''Ajax''), space elevators, magnetic levitation like Gerard O'Neill's ''mass drivers'' but on earth, lasers pushing mass up from earth, and so on [12][13][14]. For several years, I managed about $1 million in NSF awards aimed at studying the ''Ajax'' option, involving three universities and two corporations with strong connections to other agencies.…”

Propulsion integration of hypersonic air-breathing vehicles utilizing a top-down design methodology

“…The authors also point out that these programs tended to underestimate cost and overestimate performance. When the programs failed to meet promised performance and expense targets, they would be shut down [6].…”