= Hyperbolic excess speed
{title2=$v_\infty$}
The <hyperbolic excess speed> is the limiting relative <speed> far from an attracting body on an unbound <hyperbolic Kepler orbit>. Its <specific orbital energy> is $\varepsilon=v_\infty^2/2>0$. At radius $r$ from a body of <gravitational parameter> $\mu$, <conservation of energy> gives $v^2=v_\infty^2+2\mu/r$. The outgoing velocity direction as well as its magnitude matters when this orbit is matched to another attracting body's frame in a <patched conic approximation>.
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