Saturn-Shuttle
The Saturn-Shuttle was a preliminary concept of launching the Space Shuttle orbiter using the Saturn V rocket. It was studied and considered in 1971-1972.

Description 
An interstage would be fitted on top of the S-IC stage to support the external tank in the space occupied by the S-II stage in the Saturn V. It was an alternative to the SRBs.

The addition of wings (and some form of landing gear) on the S-IC stage would allow the booster to fly back to the Kennedy Space Center, where technicians would then refurbish the booster (by replacing only the five F-1 engines and reusing the tanks and other hardware for later flights).

The Shuttle would handle space station logistics, while Saturn V would launch components.

This would have allowed a space station, using a Skylab or Mir configuration with docking ports, to have been lifted with just a handful of launches. The Saturn-Shuttle concept also would have eliminated the Space Shuttle Solid Rocket Boosters that ultimately precipitated the Space Shuttle Challenger accident in 1986.