Tomorrow, the final Space Shuttle launch is scheduled. As I’ve written before, I have mixed feelings about the Shuttle: on the one hand, it’s an overly-expensive, antiquated system whose maintenance has helped prevent development of better ways to get people into space; on the other, it has captured the public’s interest, and helped advance science through the launch and support of instruments like the Hubble Space Telescope. The ending of the Shuttle program has sparked a lot of commentary, including many who seem to think this is the end of space exploration.

On the contrary: this is the golden age of space exploration. Between Cassini, MESSENGER, the Mars rovers (current and future), and many many others besides, humanity is discovering new things about our Solar System home all the time. This pace has increased rather than slowing — and I’m not even counting telescopes, both on Earth and in orbit, which can unveil mysteries such as the rotation speed of Neptune. The Space Shuttle only closes off one very small region of space exploration — low orbit around Earth.

A future mission I’m particularly excited about is the Juno probe, to be launched this August. Back in the winter, I got a letter from a third grader asking (in part) what my favorite planet is. I demurred a bit with him — I can’t say I pick favorites much anymore, since every planet has something interesting to say about it — but in my response I wrote mostly about Saturn. However, if you had asked me that question when I was in third grade, I would have quickly and definitively said Jupiter. Voyager 2’s mission to the Jovian planets was one of the major catalysts of my interest in science; I read everything I could get my hands on, especially the big National Geographic articles.

I still have a soft spot for the biggest planet. I followed the Galileo mission avidly; even years later, analysis of the Galileo data continues to reveal new things about Jupiter and its moons, including the violently volcanic moon Io. Juno holds out a tantalizing promise: if all goes as planned, it may be able to reveal exactly what the core of Jupiter is like — solid rock, or compressed hydrogen? In other words, is the core of Jupiter like the terrestrial planets (Earth et alia), or is it more like a star? Though this may seem like an abstract question, it also may help us learn how our Solar System formed, and allow us a stronger basis for comparison with other star systems.

I’m a little sad to see the end of the Shuttle program, but I’m much more thrilled with the bright present and future of space exploration.