sentences:  By eliminating the need for a large heavy-lift launch vehicle and deleting the redundant habitat delivery flight in Version 3.0, two launches from the Earth were eliminated.The net result is a current Version 3.0 Reference Mission which requires an injected mass of approximately one-half that of the 1993/94 Reference Mission.The purpose of the Reference plan, including the 3.0 update is to provide a template for a variety of Mars mission planning and technology purposes, and also to stimulate thought and further ideas for Mars missions in the "exploration community and beyond".