We can dare to dream of the stars again, if only we can achieve this small thing.

[Angrboda]

If humanity's survival really depends on a few people making major sacraifices, It would be utterly insane to tolerate the arguement "we have no right to force them to sacrafice if they don't choose to sacrifice of their own free will". At this point, all other ethical quibbles is overridden by the ethics of "the good of many outweigh the good of the the few".

I don't agree with this. The view that the good of the many outweigh the few does not supersede an individual's right to self-determination and choice.

We as a society are already quite comfortable with this, as reflected in progressive tax codes in which the freedom of the wealthy is constrained more than the economic freedom of the rest for the benefit of the larger class. This is essentially vampirism of the rich by those not so fortunate. As with most practical ethical questions, at bottom is the law of might makes right, and the lower classes have the political might to impose this asymmetrical solution upon the rich. Practical ethics, in my experience, is usually a lot uglier and dirtier than rarified sentiments.