My opinion is that the most valuable thing the human race owns is our knowledge. It has taken us a long time to accumulate the knowledge we possess. This is a collective we, meaning the human race, not me personally. Man-like mammals came into existence approximately two million ago. The oldest cave writings are about 40,000 years old. The Chinese began using wooden print about 700 hundred years ago and Gutenberg invented his press less than six hundred years ago. The first computer was invented about 200 years ago. Modern microprocessors and computers are less than one hundred years old. In the last 100 years we have learned that only half of the matter in the universe is visible. We cannot find it. These numbers of years are inexact, but do lead to the point I am trying to make. It has taken us a long time to get to where we are. Knowledge is cumulative. The more we learn, the more we can learn. The more we teach, the faster we learn.
We are unique in the universe. There may be other free-willed, thinking life forms in the universe, because of the vast distances you have to travel to move from one habitable world to another, we may never meet them. So, we must assume we have to depend on ourselves to keep viable the knowledge we have accumulated.
At some point in the future the earth will be destroyed. Even if that happens billions of years from now when our sun burns out or before by some catastrophic event, the earth will disappear. The only chance to preserve our knowledge is to learn to move between inhabitable worlds.
That leads me to the conclusion that space exploration is essential to the preservation of our knowledge. We know how to get to the moon. We put a man on the moon. We think we know how to get to Mars, but we haven’t. We certainly do not know how to get out of our solar system. And we have much further than that to go. The only way we can learn what we need to know is by trying to get further and further away from where we are. And we know accumulating knowledge takes a long time.