Establishing the infrastructure - Orbital operational requirements and options

F human missions to the Moon and Mars will require a number of activities in low Earth orbit (LEO). These include precursor activities to gather research data in life sciences to develop countermeasures to the deleterious effects of zero gravity on human physiology. Because of the inherent differences from subject to subject, a substantial number of crew will be required to undergo long periods of zero-g conditions (equivalent to the in-space legs of Mars missions—and, perhaps, for the duration of an aborted mission). Centrifuge studies will be required to determine if artificial g through rotation is an effective countermeasure. Another question to be answered is: Will periodic use of the centrifuge (e.g., X hours per day) be an effective countermeasure to zero-g effects? Many systems used for the lunar and Mars missions will require development and verification testing on orbit, with its unique zero-g, vacuum, and electromagnetic environment. Also, the technologies, systems, and operational tools and techniques for assembly, servicing, and processing of lunar and Mars vehicles will require on-orbit development and test. In-space operational activities, in support of Mars missions in particular, may include the following: 1) Receiving and storage 2) Assembly 3) Processing and launch 4) Safeing