I think the reentry vehicles are a slightly different branch of development to the X-15. The precursor programs highlight the evolution of the basic idea of "w

I think the reentry vehicles are a slightly different branch of development to the X-15. The precursor programs highlight the evolution of the basic idea of "we need something dropped from orbit to survive" on to Shuttle/Buran: https://en.wikipedia.org/wiki/ASSET_(spacecraft) https://en.wikipedia.org/wiki/ASSET_(spacecraft) https://en.wikipedia.org/wiki/Boeing_X-20_Dyna-Soar https://en.wikipedia.org/wiki/Boeing_X-20_Dyna-Soar https://en.wikipedia.org/wiki/Martin_X-23_PRIME https://en.wikipedia.org/wiki/Martin_X-23_PRIME https://en.wikipedia.org/wiki/Martin_Marietta_X-24 https://en.wikipedia.org/wiki/Martin_Marietta_X-24 https://en.wikipedia.org/wiki/Boeing_X-40 https://en.wikipedia.org/wiki/Boeing_X-40 Soviet equivalents: https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-105 https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-105 https://en.wikipedia.org/wiki/BOR-4 https://en.wikipedia.org/wiki/BOR-4 > It's crazy that it was manned back then. The Shuttle was being flown 11 years ago!