Humans are ill-prepared for space exploration. Until we create a new species that is better adapted for space travel, all missions should be of the robotic variety if they are to be cost-effective and efficient, rather than mere shows put on for public entertainment. Humans are only well-adapted to Earth. Putting a human into a hostile environment like space requires too many innovations and creates difficulty where weight and cargo space are at a premium. It is also extremely dangerous to the humans involved, although they are more than willing to risk their lives.
A space-traveling race would be small and lightweight, about the size of a mouse, with low requirements for food and respiration, requiring a smaller vessel in order to escape Earth. It might very well photosynthesize in order to supplement its diet. It would be highly resistant to radiation, gravity, and the absence of gravity. Its sole function would be to pilot a craft and react quickly to emerging opportunities and hazards in its immediate environment, eliminating the need for long-distance communication to ground control on Earth. Actual exploration and mining activity would be conducted by robotic units remotely controlled by the pilot.
I may be conservative in thinking that an intelligent species would need to be mouse-size. It is possible, though unlikely, that a species with our intelligence, or even more, could be the size of an ant, although I do not understand how except through some kind quantum mechanics hocus-pocus communication with a larger being on Earth.
I may also be mistaken in thinking that a body is needed for an intelligent species. The only advantage organic life has over computers is that we are are more effective at general tasks and general learning. The self-aware computer may exist right now in a laboratory, and no one should discount that possibility, but it is certainly not capable of translating its will into reality, while humans with their bodies do have that capability. Yet it is possible that a robot could do everything that a living organism could do and better. I don't like the idea, but it would be naive to dismiss it. Already, ordinary desktop computers with nothing special in the way of a processor or memory can very easily beat 99.99% of all chessplayers. That is enough for me to respect artificial intelligence and accept the fact that we are, all of us, obsolete to a large extent, and we are simply waiting until the next generation of technology replaces every single human profession under the sun.