**5.3 Optimizing economic returns and ISRU of NEAs**

Literally, any rock flying around is an addition to Earth resources if safely added to the Earth surface. Likewise, it can become an addition to any rocky moon or planet in its economical action range. In this regard, Vergaaij et al. [43] have economically optimized orbits and trajectories to maximize both ISRUs and economic returns in the Earth-Moon-Mars settlement ecosystem (**Figure 11**).

In the context of this contribution, it becomes logical that the Earth-Moon system, and the Moon as a springboard to low-energy access to local space permits vast economies of transport from and to NEAs. Whether pre-processing can be done in space, on the Moon surface, are still to be evaluated. It is in the author's belief that 'technically' some level of metal 3D printing should be

**Figure 11.** *Economic ecosystem of space resources in earth vicinity [43].*

feasible on the Moon surface very soon, as for a timeline for economic viability, it is still an unknown.

Notes: Blue triangles: resource locations (1) Earth surface, (2) Lunar surface, (3) NEA, (4) Martian surface, and (5) MBA. Red circles: customer locations (1) Earth surface, (2) LEO, (3) GEO, (4) SE-L1, (5) SE-L2, (6) Lunar surface, (7) LLO, (8) Lunar Gateway, (9) Martian surface, (10) Mars Base Camp, (11) SM-L1 and (12) Psyche.
