Actually, all our planetary orbits are fairly locked in position due to the gravitational interaction between the planets. If one planet's orbit changes, the others will, too, to compensate and restabilize. It takes time, but generally speaking, all of us, including Pluto and a few of it's sisters, are locked into our orbits with one another.

rtomes has a great thread on the harmonic relations of things, including planets, here.

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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.