Earth's resources are being depleted. Eventually, we will begin to run out, and to fix this problem we must look to the stars.
All celestial bodies have resources of some sort, and the closest one, our Moon, would be the easiest one to reach and scan for resources. Potentially, it could even have abundant amounts of resources, such as iridium. Since it is constantly hit by asteroids, which also have resources, this could also greatly add more resources to be retrieved, and plus there would be research possibilities. While this is great, we have some problems.
Launching rockets is expensive.By expensive, I mean millions/billions of dollars spent to launch a single thing to a place. However, we could build rockets in orbit with little costs with our minerals from the Moon.