Jan 102012
The basic layout of the final Space Transportation System, as envisioned by McD in ’71. There are a number of important differences… perhaps most importantly the inclusion of four high-pressure rocket engines on the orbiter rather than three. The SRMs were slightly larger in diameter at 156 inches.
Historical note: a number of rocket designs through the years have been 156 inches in diameter. This is not due to 156 inches being a magical performance enhancer, but due to trains. Specifically, 156 inches is the largest diameter for a cylindrical payload on a rail car that will fit through standard railway tunnels in the US.
