With ever-advancing medical technology, the prospect of achieving greatly increased lifespans during this century is becoming a real possibility. Whether one sees this development as a near certainty or a true wildcard, the implications of such an achievement could be massive. Thus it behooves us to try to better understand the implications of population aging and life extension. The SENS project involves the enhancement of the IFs model to handle longer lifespans and the refining of the forward linkages from age and health to the rest of the integrated IFs system. The enhancements are part of the Pardee Center’s efforts to provide scenario and policy analysis for the SENS Foundation.