... from Wikipedia
We see the vested interest, and it looks like the science part was a feelgood aspect. The US Constitution already provides a method of prospering that, we know it today as intellectual property, or patents and copyrights. That's the only thing that comes even close to a constitutional basis for Jefferson's fig leaf.
I suggest you read more in actual biographies of Jefferson. He was quite plain that the main purpose of Lewis&Clark was to gather scientific information. The "finding land to occupy" part was the fig leaf that he used to get funding through the Congress.