We need more reasons to send rockets to space for progression in game. What if we add telescopes! If we add a science instrument to be able to detect other worlds and other solar systems and bodies. It would add to the game.
Imagine, the only thing in the solar system is Kerbin, Mun, and the Sun. We want to explore! We send a telescope to low orbit and we discover a new moon, a new planet to explore and then we would have that accomplishment in finding new celestial bodies that we can visit!