No explanation. I’m on Venus.
Er, that is, I’m doing research on Venus, for possible story aspects. Materials, plastics, that sort of thing.
One detail that seems to be frequently missed, when someone says “How do you pay for it?” is that Venus has something valuable that would be easy to extract and ship elsewhere: Carbon Dioxide
Who needs carbon dioxide? We all do. Carbon dioxide is a nutrient for our plants, a reaction fuel for our nuclear rockets, and a source for oxygen and carbon for carbon fiber and carbon nanotubes.
But primarily I see Venus as the refueling depot for nuclear rocket reaction mass. If you want to soft-land on the moon, or other airless bodies, what better than free carbon dioxide to jet out on the way down?
If you use it on Mars, you thicken the atmosphere, and Mars needs that.
Very good. Transfer Venusian atmosphere to Mars and make both more habitable. (To some degree.)