Technology for manned Mars flight

It is important for NASA to begin development of the technologies and strategies necessary to support a Mars mission. Most of the technologies required are long lead time items and must be started now to preserve the option for Mars landings at the turn of the century. It is a common assumption that a piloted mission to Mars could be accomplished with current technology. Although this is probably true to some degree, the mass in low earth orbit would be so large that the mission would be impractical and maybe impossible. Technologies for advanced propulsion, advanced life support systems, aerobraking, and utilization of in situ resources can greatly enhance the ability to execute this class of mission.