From Hubble, discussion of Curiosity

Zelenyikot: Water is life. The water in the solar system is in ruins, but life is only here.
On the one hand, the lifelessness of Mars is sad. Hundreds of years of people's hopes for close brothers and sisters are destroyed. But if you look at the prospect of exploring Mars, its sterility is good. There will be no moral contradictions about “Can we kill them to live for ourselves?” and Greenpeace will not bother.

Hyston: I fear there will be a Redpeace that will insist on preserving the natural radiation background.