IMO manned spaceflight is extremely expensive and provides very little in the way of returns,
What are you talking about? The amount of research done in space has an extraordinary return.
But does it return more than the same money would have given if it were spent on other science projects? Or simply not spent by government at all, but left to the private economy?
We will never know. Yet I find it difficult to believe that the money the US government has spent on the Shuttle, ISS and the moon landings was well spent from a scientific point of view. Those who think that the MANNED space program is worth the money scientifically do not realize just how expensive it is compared to other major government-funded science. The superconducting supercolider would have been much less expensive than the ISS or the Shuttle and would have taught us just as many lessons, albeit in different areas. The human genome project has been largely completed for MUCH less than what was spent on any of NASA's major manned programs.
And about the ISS - whats worth more, 3 scientists in space or tens of thousand on the ground? And I am being generous. The ISS needs about 2 fulltime and one halftime crew just to keep the station itself going. As things now stand, only about 20 man/hours a week of research is being done on the station.
In fact, I have yet to see a scientist not connected to the manned space program say that what we have put into it is worth it. I would bet a considerable amount of money that we would have gotten more if we put the 50-100 billion we have spent on manned space into other science projects.
As to having a home away from earth, we won't make any significant progress towards this goal until we have a space elevator or lazer pumped launch system - something much more efficient than rockets. And unmanned missions can use this tech to - we can test it without ever having to go into space ourselves until it is economical to do so. Even then, people won't leave the planet in the numbers needed to establish an independent branch of civilization until there is an economic incentive to do so. And when such an incentive is found, no government subsidy will be necessary to get them up there. All government can do in this area is fund the launch tech and hope.
It is the intangibles of manned space flight that may make it worthwhile. How many people have been saved from the destructive evils of communism because of the PR value of the space program in the Cold War? How many children have been encouraged to put just a little more into their math and science homework? How many minorities and women have been encouraged to see so many of their number flying into space? More importantly, space travel gives people an opportunity to show their courage in a unique way. Most of the time people risk their lives for something it is to stop some great evil like the reign of Saddam Hussein or Hitler, or to save children from a fire, etc. The common thread is all of the heros of World War II, 911 and the fires out west risked their lives to stop something bad from happening. I don't want to diminish these sacrifices. Our fallen soldiers and firemen deserve the honors we give them.
However, the Columbia astronauts are different kinds of heros. They are indeed not to be any more or less exalted than all people who have given their lives in the service of others. Those others gave their lives so our worse nightmares WOULDN'T happen.....
....Yet in these astronauts, we see seven who gave themselves so that our fondest dreams COULD come happen. As the memorial on the Apollo 1 pad says, "They gave their lives so that others may reach for the stars.". They gave themselves not so that others may live, but so that others could reach out and take hold of what they strived so hard for.
Our society needs that inspiration. We have grown paranoid about taking risks. Also, To many of us, myself included, do not work nearly hard enough to achieve what we are truly capable of. The times when I have failed in life - when I have been dumped by a girl, or fired on the job, in times like those - I have remembered those brave souls who died in the Challenger. And the even braver souls who willingly stepped on board the next flight two years later. I remember just how many times the first rockets blew up in the 50's and how many tries it took to get the first probe to the moon. And how many missions still fail even given all that we have learned up to this. Despite all of this, our footsteps have touched the moon. And our probes have reached the farthest reaches of our solar system. We took the greatest gamble of all when we sent the Columbia up manned on its first flight - and we won. Within my lifetime, we may walk on Mars. Our grandchildren may see the first interstellar probe launched.
The space program teaches us as a nation and as individuals that it is worth giving our time, toil and treasure to reach our greatest potential. Even if it means taking calculated risks, even to our lives. It teaches us and our children how to handle failure - to mourn but not let it stop us from
continuing to step up to the plate. Again, and Again, and Again. To let our HOPES and DREAMS, rather than our fears and nightmares, dominate our lives and determine our actions. This lesson is priceless and it is well worth the sacrifice to have heros who can bring this lesson to the generation after ours.