[mlangsdorf]

At TL9, does a 300,000 ton, SM+13 advanced fusion pulse drive system that costs $7.2 billion count as a family operated ship? Because it takes 1.2e10 trips by that kind of freighter to move that amount of nitrogen.

A cheaper, SM+10 version of the design only costs $240 million, so more family friendly, but requires 3.6e11 trips. Which is a crazy high number.

But I agree with Fred. It is going to decades, if not centuries, to move that much stuff, and there's no great reason to do it with manned (or even robotic) cargo ships. Build a ridiculously huge mass driver or laser launch system in orbit around Venus and send frozen N2 payloads to the inner system on ballistic paths.