A little bit of both, especially where the TLI stage is concerned. A TLI stage designed around the shuttle would be significantly smaller than the Saturn IV-B and the diameter would affect volumetric distribution of the propellant load.<br /><br />The SRB/ET elements lift about the same mass as the Saturn was capable of for LEO. That mass being an orbiter. The payload portion of that mass is far smaller however because of the design.<br /><br />The shuttle can take about 48,000 lbs to LEO and originally was designed to take 65,000 lbs to LEO until post Challenger hardware mods lowered the payload capacity. But when the shuttle is launched, the whole roughly 250,000 pound orbiter is going to LEO just as the Saturn V clould launch about that amount to LEO although the only heavy lift use to LEO was the roughly 170,000 pound Skylab station. The Saturn could send approx. 90,000 pounds to the moon. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>