Deep Sea Isopod wrote:There are some people who think this money could be better spent elsewhere.
How would one respond to that?

Oh, jeez...that's a tough one...where to begin...where to begin....
There is hardly a dollar better spent than a dollar spent on the space program. The advancement of human knowledge is incalculable, and for the same reason we spend money on education and scientific research, we ought to spend money on the space program. It is integral to human long-term development and even survival. I would say that there is hardly a government program, if any, that gets better bang for the buck. When one thinks of the accomplishments of human and unmanned space flight programs, and the amount human knowledge has been increased thereby, it is almost impossible to fathom how deeply beneficial it is to mankind.
In the long term, human interactions in space are mandatory for our survival as a species, and it would be shortsighted and myopic to completely ignore space exploration, especially manned space exploration, in preference to short term goals.
The amount of money spent on the space program now is miniscule compared to programs that constitute real wastes of money. The entire NASA budget for last year is what? $16 or $18 billion - somewhere in that ballpark, and the budget has never been higher than that. Compare that with the government money spent on Boston's "Big Dig" - originally slated to cost $2.5 billion, through fraud, waste and abuse, it ballooned to $22 billion - to build a fucking tunnel. The government wasted over $100 million is unused plane tickets,. The US federal government spends $25 billion maintaining vacant or unused federal properties - annually. That's about $7 billion dollars more per year than spent on space exploration. There is a program to spend $2.6 million training Chinese prostitutes to drink more responsibly on the job Medicare/health care fraud is estimated to cost taxpayers more than $60 billion annually. The refusal of many federal employees to fly coach costs taxpayers $146 million annually in flight upgrades. A GAO audit found that 95 Pentagon weapons systems suffered from a combined $295 billion in cost overruns.
The feds spent $126 million in 2009 to enhance the Kennedy family legacy in Massachusetts. Additionally, Senator John Kerry (D-MA) diverted $20 million from the 2010 defense budget to subsidize a new Edward M. Kennedy Institute. The feds spent $3 billion re-sanding beaches.
The point being - of all the examples of money that could be characterized as "better spent elsewhere" -- NASA is far down the list of things. NASA provides results. It provides education. It provides technological development. It achieves goals and brings something back for the money spent.
So, I would say to those who would rather see NASA money spent elsewhere - why don't you start with all the even greater examples of waste? Why take something that actually does something, achieves something, and develops something - why do away with that - when there are examples totaling hundreds of billions of dollars in completely wasteful spending that occurs every year?
Beyond that - I would explain that: "... in the long run, every planetary civilization will be endangered by impacts from space, every surviving civilization is obliged to become spacefaring--not because of exploratory or romantic zeal, but for the most practical reason imaginable: staying alive... If our long-term survival is at stake, we have a basic responsibility to our species to venture to other worlds." Carl Sagan, Pale Blue Dot, 1994 "I don't think the human race will survive the next thousand years, unless we spread into space. There are too many accidents that can befall life on a single planet." (Stephen Hawking). "Let me end with an explanation of why I believe the move into space to be a human imperative. It seems to me obvious in too many ways to need listing that we cannot much longer depend upon our planet's relatively fragile ecosystem to handle the realities of the human tomorrow. Unless we turn human growth and energy toward the challenges and promises of space, our only other choice may be the awful risk, currently demonstrable, of stumbling into a cycle of fratricide and regression which could end all chances of our evolving further or of even surviving." (Gene Roddenberry, Planetary Report Vol. 1, 1981) "The Earth is just too small and fragile a basket for the human race to keep all its eggs in." (Robert Heinlein)
"There are so many benefits to be derived from space exploration and exploitation; why not take what seems to me the only chance of escaping what is otherwise the sure destruction of all that humanity has struggled to achieve for 50,000 years?" (Isaac Asimov) "Knowing what we know now, we are being irresponsible in our failure to make the scientific and technical progress we will need for protecting our newly discovered severely threatened and probably endangered species--us. NASA is not about the 'Adventure of Human Space Exploration,' we are in the deadly serious business of saving the species. All Human Exploration's bottom line is about preserving our species over the long haul." Astronaut John Young. "The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!" Larry Niven.
"I would not see our candle blown out in the wind. It is a small thing, this dear gift of life handed us mysteriously out of immensity. I would not have that gift expire... If I seem to be beating a dead horse again and again, I must protest: No! I am beating, again and again, living man to keep him awake and move his limbs and jump his mind... What's the use of looking at Mars through a telescope, sitting on panels, writing books, if it isn't to guarantee, not just the survival of mankind, but mankind surviving forever!" Ray Bradbury, Mars and the Mind of Man, 1971
"People who view industrialization as a source of the Earth's troubles, its pollution, and the desecration of its surface, can only advocate that we give it up. This is something that we can't do; we have the tiger by the tail. We have 4.5 billion people on Earth. We can't support that many unless we're industrialized and technologically advanced. So, the idea is not to get rid of industrialization but to move it somewhere else. If we can move it a few thousand miles into space, we still have it, but not on Earth. Earth can then become a world of parks, farms, and wilderness without giving up the benefits of industrialization."
Isaac Asimov.
"There are three reasons why, quite apart from scientific considerations, mankind needs to travel in space. The first reason is garbage disposal; we need to transfer industrial processes into space so that the earth may remain a green and pleasant place for our grandchildren to live in. The second reason is to escape material impoverishment: the resources of this planet are finite, and we shall not forego forever the abundance of solar energy and minerals and living space that are spread out all around us. The third reason is our spiritual need for an open frontier."
Freeman Dyson, Disturbing the Universe, 1979
"Many, and some of the most pressing, of our terrestrial problems can be solved only by going into space. Long before it was a vanishing commodity, the wilderness as the preservation of the world was proclaimed by Thoreau. In the new wilderness of the Solar System may lie the future preservation of mankind."
Arthur C. Clarke, "What Is to Be Done?" in Bulletin of the Atomic Scientists, 1992
I would argue that not only is space exploration a good use of funds, but also it is an imperative use of funds. It is a practical imperative. The human race, short of a dramatic reduction in population from 6 or 7 billion people, back down into the hundreds of millions, and back to a basically agrarian society, is doomed if it stays on Earth. What would be a better use of funds?