I don't believe we have a solution to human-vs.-machine question, which is better to go to space. On human side, many times both opponents and proponents of spa

I don't believe we have a solution to human-vs.-machine question, which is better to go to space. On human side, many times both opponents and proponents of space robotics pointer out that for big exploration programs humans become more economical - as you still can't reproduce human abilities in space with robotics while spending the same resources, if you have big enough goals. Humans have other advantages too. Majority of people in modern NASA workforce say that they become interested in space when watching human space programs. So far no robotic achievements have psychological impact equal to humans in space. Next, there is eternal "explorational" argument - you don't really "get" space into your domain until you're actually maintain physical presence in it. Unless you at least fly on LEO, you aren't in space. Until you fly to the Moon, you don't "use" it. Etc. Next, while robotics is advancing with leaps and bounds, human spaceflight doesn't stand still. In 1990-s Dan Goldin, NASA administrator, ordered an evaluation of some options of going back to the Moon. The cheapest was using existing rockets - less than 30 tonns on LEO per launch - and the program was for less than a billion dollars. Note that a bunch of technologies used today in manned spaceflight are vastly superior to those used during Project Apollo. Getting to orbit becomes cheaper and safer - SpaceX is another evidence to that, but it's not at the end of technical possibilities. When you get spaceflight cheap enough, there is no stop for curious individuals to go to the Moon in person. Same for Mars - at least. What technologies will be employed for traveling in space - that's another matter. With cheaper and cheaper energy it will progressively make sense to make more and more safe - even if heavier - human spacecrafts. The more infrastructure in space we have - be it LEO stations, fuel depots on orbit, Moon-based fuel production, Mars navigational network etc - the easier it will be to launch both robots and humans. It's hard for me to see why we won't want to go.