I've only heard "my relatives" or questions like, "are they of any relation to you?" I've never heard anyone call their relatives their "relations" and it wouldn't be proper english if they did (in my opinion). Still, Merriam-Webster does list the two as synonyms.

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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.