Space Shuttle Expendable Second Stage studies (1970-1971)

[galopujacy_jez]

The predecessor of Shuttle-C was a different beast, studied in 1970-71 called Expendable Second Stage that would have use a modified S-2 stage on top of a reusable winged first stage (same used by then-projected Shuttles. There are a couple of reports on NTRS on this, I personally discovered six months ago. The studies was conducted in parallel to Shuttle Phase B studies. There is an illustration and a brief note on the ESS in third edition of Jenkins' magnus opus on Shuttle, but not sufficiently enphasized IMHO. It's slightly OT, but I post here an art of the ESS.

Concept art of the ESS on Number Station's flickr and two b&w illustrations from Phase B reports on the ESS.
flic.kr/y/3StZh29

12 volumes of the Phase B final report on the Expendable Second Stage with the Reusable Space Shuttle Booster
https://ntrs.nasa.gov/api/citations/19730006138/downloads/19730006138.pdf
https://ntrs.nasa.gov/api/citations/19730006139/downloads/19730006139.pdf
https://ntrs.nasa.gov/api/citations/19730006140/downloads/19730006140.pdf
https://ntrs.nasa.gov/api/citations/19730006141/downloads/19730006141.pdf
https://ntrs.nasa.gov/api/citations/19730006142/downloads/19730006142.pdf
https://ntrs.nasa.gov/api/citations/19730006143/downloads/19730006143.pdf
https://ntrs.nasa.gov/api/citations/19730006144/downloads/19730006144.pdf
https://ntrs.nasa.gov/api/citations/19730006145/downloads/19730006145.pdf
https://ntrs.nasa.gov/api/citations/19730006146/downloads/19730006146.pdf
https://ntrs.nasa.gov/api/citations/19730006147/downloads/19730006147.pdf
https://ntrs.nasa.gov/api/citations/19730006148/downloads/19730006148.pdf
https://ntrs.nasa.gov/api/citations/19730006149/downloads/19730006149.pdf
https://ntrs.nasa.gov/api/citations/19730006150/downloads/19730006150.pdf

And the "STATIC AERODYNAMIC AND CONTROL INVESTIGATION OF AN EXPENDABLE SECOND STAGE WITH PAYLOAD ALONE AND WITH DELTA WING BOOSTER"
https://ntrs.nasa.gov/api/citations/19710029200/downloads/19710029200.pdf