Re: Can we send supplies in an unmanned satellite to other planets to get later

In principle, yes, of course we could. Indeed from the point of view of 
risk, there could be something to gain in sending a prepacked set of 
supplies to Mars at one launch window, and, on confirmation of its safe 
arrival, send the manned ship , since launch windows occur every 2 years. 
Dr Robert Zubrin, author of the Mars Direct project, goes one better, and 
suggests that this first unmanned lander actually extracts fuel from the 
local environemnt while it awaits the arrival of the manned expedition. 
This ship could  therefore be much smaller than is usually predicted, since 
it does not have to carry its return fuel. 
 Zubrin calculates that, rather than costing the prohibitive 400-500 
billion dollars which experts put down as the cost of President Bush's SEI, 
costs could be reduced to as little as 25 billion dollars over an 8 years 
development period, including the first expedition, and that, once in 
business, biennial missions to Mars could be had for 2 billions per year
 Gradually, over two decades, a substantial Antarctic scale base could be 
built up, for a very reasonable ongoing cost. Zubrin even proposes that, 
after initial Government input to establish the reconnaissance and basic 
technologies, the settlement of Mars could be a commercial/private venture 
rather than a Big Government project perhaps like the Mayflower expedition 
of 1620!
 Variants on this theme involve setting up unmanned base camp on Phobos- a 
Martian moon, with very low escape velocity, and fuelling the final 
landing/return from Mars using fuel derived from Phobos and Mars.
 The use of asteroids or comets to provide water, and fuel is another 
possibility- very attrative, since, again, very little energy need be 
expended rendezvousing with these bodies. Such an approach also offers 
potential routes to avoiding or surviving the "Armageddon" Impact scenario 
, by mining out Near Earth space of possible Impactors in the interests of 
space based industry and dispersed human colonies! A long term prospect 
perhaps, but since the alternative is an Impact costing billions of lives 
and trillions of dollars, surely not to be sneered at? Some of us argue 
that, without building such an Extraterrestrial civilization, the concept 
of longterm prospects has no meaning.