"A NASA-funded study found that a human-rated Delta IV heavy rocket could be a cheaper route to the International Space Station than NASA's Ares I crew launch vehicle. But the human-rated United Launch Alliance rocket would be less expensive only if the Ares V heavy-lift moon rocket development is deferred, the Aerospace Corp. study reports. And the Delta IV alternative could add two years or more to the "gap" in U.S. human access to orbit if it starts this year, according to the unreleased study obtained by Aviation Week."
"Finally, we considered both development and full life cycle costs. I cannot go into the details of this analysis in a speech, and in any case much of it involves proprietary data. We have shared the complete analysis with the DoD, various White House staff offices, CBO, GAO, and our Congressional oversight committees. Our analysis showed that for the combined crew and heavy-lift launch vehicles, the development cost of an EELV-derived architecture is almost 25% higher than that of the Shuttle-derived approach. The recurring cost of the heavy-lift Ares V is substantially less than competing approaches, and the recurring cost of an EELV upgraded to meet CEV requirements is, at best, comparable to that for Ares I. All independent cost analyses have been in agreement with these conclusions."