is an outgrowth of its vitality
And ... America is finished in this department.
America is aging in the same manner as Europe. Its people are looking primarily for safety in retirement. Its thinking leans more to "How can we save lives?" than to "How can we advance civilization?". The first question deals with what we have ... while the second deals with what we might get ... if ... we venture.
There is a certain amount that individuals must have before they become complacent about their future. They must perceive as a guarantee that they will have in their lives ... a livable home, a dependable food supply, transportation, and access to reasonable medical care. Oh, and there is one other thing that is high in importance ... entertainment.
America has all of this in abundance. Though every individual may not agree ... most do ... by their complacency. They agree, though they may protest ... a little. These are not risk takers. They are "retired" from those concerns. Simply put, a plasma TV is more important than knowledge about Mars. After all, what tangible good will that bring us? How would our situation be improved if we risk a ton of money. Better to spend it on new distractions. Bread and circuses.
There will always be a small percentage of the population who want to know as an end in itself. They will shoulder the burden of carrying the rest of an increasingly fat population ... fat in mind as well as in body. Their position will be more as "servant" than "example". NASA is as good as dead though it may continue for many decades to come ... but ... it's glory days are, most assurably, over.
What the future holds
The remaining shuttle fleet is presently grounded. If they fly again, it will be a minor miracle. They will not be replaced though there will be much talk about it ... eventually shouted down by cries of "We must first do something about the poor!" The once ambitious space station is cut back constantly and will become a floating pile of barely usable junk in a decade or two.
Our great ambition will be to send little robot thingies to other worlds to explore ... safely ... the entire solar system at the pace of a wandering snail. When two thirds of them fail, funding will be cut back as well (even though these things are cheaper than manned missions) because they will become the new standard of "expensive". There will come a time when sending a simple communications satellite into orbit will be too costly or difficult and the higher tech end of our civilization will fail. (Perhaps these hi-tech jobs can be outsourced? ... thought ... outsourced ... hmmmm ...)
Our gaze will be firmly fixed where it belongs ... on the earth, most specifically in the dirt where politicians wallow ... their natural element. But ... not to worry ...
China to the rescue
China is the world's future. Its people are hungry. When a flag is first firmly planted by a human hand on Martian soil, you can rest assured that it will be Chinese. It may take several decades, but they will get there eventually.
The reason is the centuries of squalor most Chinese have lived in ... and ... most importantly, the recent decades of extreme oppression they have endured at the hands of their own rulers. When people are kept down in that manner they tend to bounce back up very high when released. Witness the oppression of the Catholic church in Europe during the dark ages. When it ended, it resulted in the Renaissance and virtually all the present high-end civilization.
And they have another advantage - Confucius. Their chief philosophy is basically non-mystical. So when the present regime collapses [as it must, since material progress is incompatible with slavery] they will be in a fine position to regenerate the earth's civilization. They will be lean, hungry, motivated and unburdened by the leftovers of Christian inanity as was Europe in the Renaissance.
I predict that they will take over leadership in the sciences and become the earth's dominant nation before the present century is out. America will be "resting" and watching on an extremely large TV from an extremely robust sofa designed to hold 300 pound individuals and very large bowls and boxes of popcorn, soda, pastries, pizza and candy. We will have a fine life indeed ... free from the requirements of physical or mental "action".