There are many Centaur upper stages and a few other objects in the junk yard orbit just beyond the geosynchronous orbit. Is there any reasons why this stuff could not be reused?
There are cryogenic tanks that could eventually serve the oxygen production activities on the moon. There are rocket engines that could be used for landing on and launching from the moon's surface or for space tugs. There are some satellites with solar panels and some interesting electronics. Why isn't anyone talking about all this stuff as an In-Situ Resource?