Not too sure about economics. Nat would be nice.
We have 4 AI's to trade with; Boudica has only GP and Nat available, at a loss (as she's unlikely to depart with both).
First turn, I'd trade for GP, Nat and PP, next turn we can trade for either RP (going rifling) or Chemistry (going steel). This'd mean trading at a loss with Boudica, but in the end give us more for Astro. Note that Frederick hasn't teched RP yet, so if we want that, we should trade with him in the first round.
After the second round, we can sell it to the non-trading AI's for cash as well.