Anything which is physically possible can always be made financially possible; money is a bugaboo of small minds.
Robert A. HeinleinBut does Man have any 'right' to spread through the universe? Man is what he is, a wild animal with the will to survive, and (so far) the ability, against all competition. Unless one accepts that, anything one says about morals, war, politics, you name it, is nonsense. Correct morals arise from knowing what man is, not what do-gooders and well-meaning old Aunt Nellies would like him to be. The Universe will let us know - later - whether or not Man has any "right" to expand through it.
Robert A. HeinleinSelfishness is the bedrock on which all moral behavior starts and it can be immoral only when it conflicts with a higher moral imperative.
Robert A. HeinleinOn two subjects the overwhelming majority of people regarded their own opinions as Absolute Truth, and sincerely believed that anyone who disagreed with them was immoral, outrageous, sinful, sacrilegious, offensive, intolerable, stupid, illogical, treasonable, actionable, against the public interest, ridiculous, and obscene. The two subjects were (of course) sex and religion.
Robert A. Heinlein