They did. And actually, it was probably closer to 10,000 BC, when they first began using pack animals, also called "hayburners," and as we all known, hay grows in sunlight, therefore it's solar...

So is firewood.

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If I set the budget, we'd have Ares and more. Unfortunately, I don't set the budget, and Ares is just too expensive and too far out for us to accomplish our goals within the budget we were given.

If we halt the ISS, all versions of Ares, and transport Orion and Altair aboard DIRECTv3's Jupiter family of Shuttle-Derived Launch Vehicles, we just might make it back to the Moon by 2020.