“I got a letter from a reader who wrote to berate me on the expense of the space program and telling me I ought to be ashamed for not spending the money on the cities and the poor.
I wrote back to say that the people of the United States spend exactly as much money on booze alone as on the space program. And if you add tobacco, drugs, cosmetics, and worthless patent medicines (and chewing gum, suggests Carl Sagan), then we spend far more on these useless-to-harmful substances than on space exploration.
I asked her if she indulged in any of these vices and if she would consider sponsoring a movement to have the people give up these things and donate the money equivalent to the cities. (Of course, this would throw a hell of a lot of people out of work, which shows how difficult it is to do anything.”
by Isaac Asimov in 1969, some days after Apollo 11 landing on the moon.
I saw it here: Why Spend Money on Space Exploration? Isaac Asimov’s Witty 1969 Letter
The surface area of Mars is exactly as large as the land area of the Earth. A thorough reconnaissance will clearly occupy us for centuries. But there will be a time when Mars is all explored; a time after robot aircraft have mapped it from aloft, a time after rovers have combed the surface, a time after samples have been returned safely to Earth, a time after human beings have walked the sands of Mars. What then? What shall we do with Mars?
There are so many examples of human misuse of the Earth that even phrasing this question chills me. If there is life on Mars, I believe we should do nothing with Mars. Mars then belongs to the Martians, even if the Martians are only microbes. The existence of an independent biology on a nearby planet is a treasure beyond assessing, and the preservation of that life must, I think, supersede any other possible use of Mars.
–Carl Sagan in “Cosmos”, Chapter V: Blues for a Red Planet, 1980.