Economics (was Critical time)

For the Moon specifically, since no suitable propellant is found on
the moon, a propellantless techology (i.e., mass drivers or thethers)
will eventually be most successful, if mass launched increases
continually. But we don't have that assurance that launches from the
Moon will increase. You're making lots of sense here. Whenever I mention lunar mass drivers, or use of lunar resources in HEO, it's always in the context of a massive SPS construction program,and/or orbital habitatprogram. In those cases, launches from the moon will increase. But I'll be the first to agree that use of lunar ores makes little sense in any operation much smaller than this. For example, I had an exchange with one fellow who was proposing a moonbase, lunar mine, and mass driver for construction of large GEO communication satellites. I told him that the tonnage needed in GEO was much too small to justify such an investment. On the other hand, I spoke to another fellow who insisted that Island One should be built from Earth launched components, as he felt the undeniably cheaper resource extraction and component manufacturing available on Earth would outweigh the lift costs savings of the lunar option. I feel that the truth lies somewhere between these two extreme opposite viewpoints.