

Lagrangian Point - thisjepisje
http://en.wikipedia.org/wiki/Lagrangian_point

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ColinWright
What is not commonly known is that just as we can do a "gravitational assist"
or "slingshot" around a planet, we can also perform a gravitational assist off
a Lagrangian point. Specifically, we can "bounce" off L4 or L5 as if it were a
body of negative mass.

Not sure it's ever been done, though, but the theory is sound.

