space transportation network

earth's moon has oxygen in the lunar dust 

but no hydrogen 

and both oxygen and hydrogen is needed to make water 

so in the beginning hydrogen will probably be transported 

from earth to the moon 

by reusable rockets 

but as more and larger colonies are built on the moon 

more hydrogen will be needed 

and there is no reason to deplete earth's hydrogen resources 

for the benefit of the moon colonies 

so then hydrogen will be transported 

from the atmospheres of other planets 

such as jupiter, saturn, uranus and neptune 

but in the beginning of space colonization 

it could be difficult to extract hydrogen from gas planets 

so it would be preferable to extract hydrogen 

from asteroids in the asteroid belt 

and from the moons of other planets in the solar system 

the atmosphere of the moon titan contains a lot of nitrogen gas 

which will be needed together with oxygen from the moon 

to create air for the colonies of earth's moon 

and nitrogen will be required as fertilizer for agriculture 

on earth's moon 

and as colonies are created on mars 

and on most moons in the solar system 

then matter will be exchanged between that planet and those moons 

so a transportation network is needed 

very big maglev launchers will be built on the surfaces of every moon 

to launch cargo spacecraft containing matter 

that the markets of the target destination requires

and very big maglev launchers will be built in the asteroid belt 

and those maglev launchers will anchor / attach to very big asteroids 

in the asteroid belt 

to launch cargo spacecraft containing matter 

that the markets of the target destination requires 

the cargo spacecraft will use rocket boosters 

to navigate into orbit of target moon or target planet 

in order to gravity brake 

and a reusable rocket will launch from the moon 

to pickup the cargo spacecraft 

and then return to the surface of the moon 

where cargo will be unloaded from cargo spacecraft 

and new cargo will be loaded onboard the cargo spacecraft 

and then the cargo spacecraft will be launched 

from a maglev launcher on the moon's surface 

toward another moon or planet or the asteroid belt 

if the cargo spacecraft is sent to mars 

then the cargo spacecraft will use its rocket boosters 

to navigate into the orbit of mars 

in order to gravity brake 

and a reusable rocket will launch from mars 

to pickup the cargo spacecraft 

and then return to the surface of mars 

where cargo will be unloaded 

and new cargo will be loaded onboard the cargo spacecraft 

and then a reusable rocket will lift the cargo spacecraft 

into the orbit of mars 

where the cargo spacecraft 

will connect to a maglev launcher orbiting mars 

and that maglev launcher will launch the cargo spacecraft 

toward another moon or planet or the asteroid belt 

gemini ai complains that it would be impossible to gravity brake 

around earth's moon 

if the cargo spacecraft is sent from the asteroid belt 

but in my opinion 

the cargo spacecraft could swing by earth and earth's moon 

a few times in order to gravity brake 

but gemini ai complains that it still would be difficult 

and gemini ai insists 

that the cargo spacecraft should use its rocket booster to brake 

and not only gravity brake