First, thanks for a polite and intelligent answer: it is most appreciated. I expect the next part is going to sound angry and a little scared, and that does reflect my emotions, but not with you!

Water purification is an excellent example of something that we could easily have done independently without actually spending billions of dollars to go to space.

All the examples in that infographic fit into the same category. The idea that rechargeable batteries would not have been invented if there were no space program is ludicrous.

(I would also note that nearly all of these are 40 years old or more...)

Your exercise is also self-negating, because this island in space doesn't exist and might never exist. In your example, if there were problems on land, it would be better to solve them directly than to build an artificial island in the middle of the sea at huge expense, move thousands of people there, and somehow hope that these people would solve the problem.

IF we had infinite resources, then your idea would be fine. But we don't. We aren't spending even 5% of what we would need to not kill the planet. Every year we emit more CO2 than the previous year. Undertakings like manned space travel are wildly expensive in money and energy and nearly all the results are not at all relevant to the issue of saving our biosphere.

I grew up with the space program - I saw the first steps on the moon live - and I was its biggest fan. But I expected we'd do something about the destruction of our ecosystem and we haven't - quite the reverse. Most of the CO2 ever emitted by humans has been emitted in the last 30 years.

Now our house is on fire and we're just letting it happen. Having a space program would protect us against catastrophes that happen tens of millions of years apart, and we should do it, but only after we have at least stabilized our biosphere. What we are doing now is like planning our great-great-grandchildren's retirement fund while our family sits in a burning house.