QUESTION:
Is it a possibility to build a Martian space vehicle refuelling base?

ANSWER from Andrew Petro on August 15, 1997:
Yes, it is not only possible, it may be a good idea to use a Martian base to
refuel space vehicles.  Since Mars has an atmosphere of carbon dioxide and
it has some water (mainly in the form of ice) we may be able to make oxygen
to use as a rocket propellant and maybe fuels like hydrogen or methane right
there on Mars.  We could use these propellants for the space vehicles
returning to Earth.