Once you are in orbit, anything else is possible. Because if you can get something small to orbit, you can get a lot of small things (such as additional fuel)

Once you are in orbit, anything else is possible. Because if you can get something small to orbit, you can get a lot of small things (such as additional fuel) to orbit, to reach escape velocity. That is because once in orbit you no longer have a need to reach the next velocity stage as rapidly as possible, which is why ion engines are so efficient but can only be used after LEO.