Human rated Delta IV Heavy Constellation architecture impacts

This paper summarizes the findings of several assessments of the technical, cost, and schedule feasibility of replacing the Ares I with a human-rated evolved expendable launch vehicle (EELV), and its first-order effects on the overall Constellation architecture. The paper examines if an EELV, specifically the Delta IV Heavy (Delta IV H), could serve the crew launch function, and if so, determine the impacts to the launch vehicle, production, and launch-base processing, and fabrication. Also included is an assessment of the effects on the Constellation architecture elements of replacing Ares I with a human-rated version of Delta IV H (HR Delta IV H), estimates of the associated cost and schedule (including impacts to Ares V cost and development time), and identification of impacts on national security space (NSS) if NASA utilizes an HR Delta IV H for low Earth orbit (LEO) human missions.