Manned Mars missions using propellant from space

A recent discovery (8/14/92) of a near‐earth object containing materials potentially useful for space activities could perhaps change the entire way humans access and operate in space. A near‐Earth object (♯4015, 1979 VA, comet Wilson‐Harrington) contains water ice that could be used for space propulsion. In addition, this type of object may contain structural and lifesustaining materials (complex hydrocarbons, ammonia and/or bound nitrogen compounds) for space structures, manned planetary bases, or planetary surface terraforming. The retrieval and utilization of rocket propellant from near‐Earth objects, for manned Mars missions in particular, has been investigated and the benefits of this scenario to over performing a Mars mission with terrestrial propellants have been documented. The results show water extracted from these objects and retrieved to Earth orbit for use in going to Mars may actually enable manned Mars exploration by reducing the number of Heavy Lift Launch Vehicle (HLLV) flights or eliminating the need for HLLV’s altogether. The mission can perhaps be supported with existing launch vehicles and not required heavy lift capability. Also, the development of a nuclear thermal rocket for this alternate approach may be simplified substantially by reducing the operating temperature required.