Page "Single-stage-to-orbit" Paragraph 86

A detailed study into SSTO vehicles was prepared by Chrysler Corporation's Space Division in 1970 – 1971 under NASA contract NAS8-26341.

Their proposal ( Shuttle SERV ) was an enormous vehicle with more than 50, 000 kg of payload, utilizing jet engines for ( vertical ) landing.

While the technical problems seemed to be solvable, the USAF required a winged design ( for cross range ) that led to the Shuttle as we know it today.