True — I simply added up NASA’s budget in constant dollars through the moon landings for maximum effect, but the Apollo program in isolation would have been les

True — I simply added up NASA’s budget in constant dollars through the moon landings for maximum effect, but the Apollo program in isolation would have been less. (Still took an estimated 400,000 personnel to pull it off, though!) To my untutored eye, your $200bn+ doesn’t sound out of the range of likelihood, plus or minus — you’re basically looking at an ISS with a number of novel capabilities, plenty of redundancies, and assurance that the crew won’t end up dead from hard radiation along or after the trip, so assume at least $150bn in engineering+build and another $10-15bn to get 500 tons or so of spaceship into orbit. Add in Martian lander and rover costs, new personal equipment, any novel work on propulsion, power, radiation, and life support ... what were these guys thinking, anyway?