The National Launch System was a study authorized in 1991 by President George H. W. Bush to outline alternatives to the Space Shuttle for access to Earth orbit.
One Rocket Concept Considered was a 450 Ft tall 27.58 ft Diamiter Core Stage with a 46x100 Ft Mars Payload Accomidation Fairing with 8 Energia Boosters
Some Issues/Concerns noted
Reliance on a Politically Unstable Foreign Source for Flight Hardware
Reliance on a Two Nation Consortium for Hardware (Boosters-Ukrain, Engines-Russia)
Source NASA_NTRS_Archive_19960041001.pdf