Production possibility frontiers for a cis-lunar transportation system

A cis-lunar transportation system (CLTS) can be designed to provide combinations of two services: lunar export and lunar import. The set of all such combinations is called the production possibility frontier (PPF), which in turn is a familiar concept from micro-economics. The CLTS envisioned operates flights between space stations in low Earth orbit (LEO) and low lunar orbit (LLO), and flights between LLO and lunar base (LB). A system of 28 equations is presented which models the interactions between structure, payload and propellants in the CLTS. The traffic ratio of LB-LLO-LB flights to LEO-LLO-LEO flights is determined to be a key parameter for achieving high lunar export/import ratios. It is also shown that the CLTS can achieve a significant net mass gain in LEO, thus creating the possibility of lunar exports generating revenues for the colony by competing on price in LEO with terrestrial exports.