The human aspect of living in a colony on another moon or planet is also often underestimated. I miss the snow and change of seasons in Minnesota quite often. How much worse will it be for people living on other worlds, hermetically sealed off from the environment.

It doesn't personally appeal to me at all. I'm sure, though, that over time (a long, long, time) we'll set up outposts on other planets/moons within our solar system.

Interesting essay – you have lots of thought put into this.

I’ve got some comments I’ve assembled over the past few nights.

Survival

On the issue of survival as a major reason for space exploration: over the years I’ve come to a personal opinion that this is not a reason for exploring space. When it comes to the survival of the human species, the biggest threats come from terrestrial sources. If we are to survive over the long, long, term (where space exploration could come into play), we must first survive over the shorter term. Even then, I am highly (highly!), skeptical that we will be able to set up any viable populations on other planets within our solar system that would be entirely self-sustaining and capable also of growing a space transportation technology themselves with the available resources and expertise. Remember, if we are talking about survival of the human species using space travel, any population we place elsewhere must also be spacefaring, or else we are not providing for the survival of our species – only postponing the inevitable. Consider the resources and expertise that will need to be present within those colonies to propagate humanity. Even with that, we are almost surely limited to propagating our species within our solar system, since interstellar travel exists entirely within the realm of science fiction both now and in the unforeseeable future – regardless of how much I would wish it was otherwise.

If we care about our children’s children, we will pay attention to our environment, and develop a way to protect Earth from internal and external threats. That may involve space technology, but it does not require that we explore space – at least with crews.

Economy

Asteroids contain a lot of useful and valuable metals such as nickel and platinum, and in grades that have been described as “spectacular.” These are undoubtedly monumental treasures, if they could be mined. Heavy manufacturing can’t be *relocated* off-planet without incurring a hefty increase in costs (which would be passed on to consumers), but it’s possible that “in-place” refining of the metals mined from asteroids might be achievable. I expect that the capability that would be enabled most, then, would be in-space construction using the materials mined and refined in space.

The idea is that our federal space program should nurture commercial space activities to create jobs, wealth, and to enable currently impossible endeavors. Also, it should undertake exploration activities that commercial space ventures cannot at this time carry out.

Technology

Spinoffs are a sometimes misunderstood benefit. We can’t justify space exploration by claiming that such an endeavor might produce technology or products that someone else can sell or use. First off, it’s not cost effective. We don’t pursue medical treatment breakthroughs because it might result in longer-lasting power steering fluid for our cars. We don’t pursue a better thermal protection system for our spacecraft because it might result in a coating for construction materials that makes it withstand fires better. If we want to develop a capability or a technology product, we pursue it directly. The pursuit of a human spaceflight program doesn’t lead to the cheaper development of technology products compared to developing them directly, and I don’t believe it leads to the development of technology products quicker than other aerospace, defense, or manufacturing pursuits do.

Discovery

I am a very curious person, and I would love to see more space exploration. Much more. I wonder what the average person out there would say on this? How much taxation is too much in pursuit of space exploration? That’s where the support evaporates. I see the explosive growth of commercial space ventures as a necessary precursor to the broader human exploration of our solar system on the scale I’d like to see.

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For the next 50 years, I would not plan anything – we have no idea where things will go after the first and most important goal. Let’s get first things done first. I think John Marburger had some really great thoughts on this (http://www.moontoday.net/news/.....?pid=19999):

“If we are serious about this, then our objective must be more than a disconnected series of missions, each conducted at huge expense and risk, and none building a lasting infrastructure to reduce the expense and risk of future operations. If we are serious, we will build capability, not just on the ground but in space. And our objective must be to make the use of space for human purposes a routine function.”

“Exploration that is not in support of something else strikes me as somehow selfish and unsatisfying, and not consistent with the fact that we are using public funds for this enterprise, no matter how small a fraction of the total budget they may be.

If the architecture of the exploration phase is not crafted with sustainability in mind, we will look back on a century or more of huge expenditures with nothing more to show for them than a litter of ritual monuments scattered across the planets and their moons.”

If commercial space transportation can be successful, that’s the key to opening the door to bringing the solar system within our “economic sphere.”