An observation

In an earlier post, the feasibility of mining asteroids was discussed.  It occurred to me that all discussion seems to point to the assumption that every mission has to originate from Earth and every destination has to be an immediate return mission.  But what if people could stay in space for years at a time?  What if you could mine an asteroid for awhile then jump to the next one when it made sense to do so?

A moon base could serve as a jump off point for mining missions.  Or it could serve as a jump off point to create more jumping off points that could eventually support mining missions on a continual basis.  In order to reach this goal, you have to start somewhere.  The most logical point is a moon base which can sustain a long term presence in space.  The main purpose of the moon base would be to launch missions from the moon, as opposed to launching them from the Earth.  I suspect that I have written this before, but the logic of it is inescapable.  The main hurdle of space commercialization is launch cost.  Those costs can be reduced to manageable proportions if the launches were conducted from the moon.

Update:  moments later

It may that the cost of getting stuff into orbit is too high, yet there was a launch system contemplated briefly by NASA in the early sixties that would have been able to put 550 tons into LEO.  This system, called a Sea Dragon, would entail a launch from the open ocean.  The rocket would be towed from the mainland, then rotated into position where it would be launched.  The Sea Dragon concept was proved, so it wasn't some way out idea.  Launch costs were estimated as 1/4 of the costs of the eventually operational Saturn V rocket that took astronauts to the moon.

The key to me is not the launch costs.  It is the mass of what could be put up there at one time.  You have to consider that 550 tons is an awful lot of stuff on one launch.  Now if you were to put enough stuff up into orbit, you can start doing things.  One example is that you could launch multiple missions on just one launch.  For instance, one estimate for the amount of mass needed for a Mars mission is 170 tons.  Imagine putting up materials for 3 missions from just one launch.  Or one mission to do 3 times as much stuff.   On your mission to Mars, you could set up the capability to do some mining, or prospecting for mining.  Try to imagine the reaction if the astronauts upon return had marketable amounts of imports from the journey.