KK suggests: The idea is to float up the 'package' to be put in orbit/shot into space, via a combination of airship/solid fuel rocket. So that in can be engulfed and accelerated by the orbiting Space Cannon ( whether DC or AC to be decided. ) Now the pathway of the package wil consist of a series of segments making up an overall curve this initally will descend to the Earth then 'Straighten up' for Earth Orbit or shoot off into space if it is supplying stores to Mars. This implies that the acelerating coils are indifferent orbits and one has the problem of syncranization. However if the more massive power generators are put in the same orbit and the coils held in their correct postion by retaining cables leading outwards, then the problem is got over. These coils will be pulling against their cables. When the package applies opposite momentum then this retaining action will correct the applied torque, only the force at the centre need be considered. This will bring the centre of gratities into a lower orbit. But I have suggested elsewhere a Polar Orbit so that by using either reverse DC or low frequency AC, the cannon can use the Earth's Magnetic Field as an accelerator. Note this implies inorder to keep to the planetary plane, the package acceleration will have to occur at the poles!
What we need is a proper commercial space industry. We currently have a fairly decent one - satellites are big business, but I mean something more like Virgin Galactic. We need to establish a permanent human base somewhere. The problem is, there's very little in space worth leaving Earth for, and it's extraordinarily costly.