We are about to send our fifth? rover to Mars in a few weeks....why not to a moon of Mars or a moon of a outer planet instead?
I understand keeping the NASA budget perpetually funded and all but still..
Done did. 2005...............
https://en.wikipedia.org/wiki/Huygens_(spacecraft)
There is growing interest in returning to Neptune and Uranus (please...behave). This article does a nice job of laying out the pros and cons, chiefly The problem with outer solar system exploration is, you want a spacecraft moving fast enough to reach its intended destination in a decade or so but too much speed makes slowing down to enter orbit out of the question
I don't believe Congress was granted an enumerated power in the Constitution to create NASA - it's not serving a military function, and the power of pursue pure exploration isn't an Article 1, Section 8 power.
That's said, I love space exploration and think mankind got a lot out of Veejer and New Horizons etc. I want to return to Neptune and Uranus (again..behave children).