NON-PROPULSIVE ACCESS TO THE MARTIAN SURFACE
Michael A. Pelizzari
When humans begin to systematically explore and settle Mars, the addition of rocket exhaust gases to the thin Martian atmosphere will irreversibly alter its composition, and its reactivity with exposed surfaces. Scientists on Mars will then be hampered by the challenge of distinguishing anthropogenic from pristine features of their objects of study, a fact that will erode the value of their contributions to comparative planetology. The problem can be avoided, or at least mitigated, by conducting as much activity as possible using emission-free vehicles and power sources. Transportation between ground and space can be accomplished without rocket propellants, either by shooting payloads into space with guns (mass drivers), or by transferring momentum to them through ultra-long cables (space tethers). The Gun Transportation System would consist of electromagnetic “coil guns” or conventional expanding-gas guns, either of which must be hundreds of kilometers long to achieve escape velocity at human-survivable accelerations. The Cable Transportation System would consist of skyhooks, space elevators, and other tether-based elements, hundreds or thousands of kilometers long. Both transportation systems would be easier to deploy at Mars than at Earth, due to its smaller size, lower gravity, and thinner atmosphere.