Abstract
In-Situ Resource Utilization is viewed by most as the basis for a successful manned exploration and settlement of the solar system. It is as its name implies, the “living off the land” that is a necessity for any untethered manned activity. The goal of ISRU is to allow settlements on the Moon and Mars and beyond to live with minimal if any dependence on the shipment of raw materials from Earth. The existence of a broad spectrum of elements on the lunar surface and on Mars gives hope that in principle it is possible to build a sustainable infrastructure on both these bodies that is based on local resources.