Re: Breaking an orbiting object
> Breaking an orbiting object (e.g., to bring an asteroid down towards the earth orbit around the sun) costs as much energy as accelerating it.
You can use Earth's atmosphere to slow it down. Or Mars', if you are shipping there. SpaceX Starship plans to lose 99% of its delta-v by aerobraking during Mars descent.
> infinite available energy
That's pretty much the case in space. Vast energy from the sun, with no clouds or night time to interrupt it. Either use directly with mirrors to concentrate it, or else create electricity via solar panels. Either way, in space you can build fast structures without them needing to support their own weight against gravity. Transport is cheap because there is no friction in vacuum.