When does it make sense to build a starship? Back in the late 1960s, Freeman Dyson went to work on the question of how much an interstellar probe might cost. Extrapolating from nuclear pulse propulsion and the state of the art in spacecraft design as then understood, Dyson arrived at an estimate of $100 billion to build the craft, which translates into roughly $650 billion today. Though stark, that figure is by no means as eye-popping as one of the estimates drawn up by the original Project Daedalus team: $100 trillion in 1978 dollars.
This gargantuan figure is obviously untenable, and a product of inferior physics. That would obviously change if new physics were discovered, which is something not out of the realm of possibility. To read the rest of the article, click here.