# Relationship of 'C3' to Delta-V for interplanetary missions

In what way does the concept of 'C3' relate to 'Delta-V' in interplanetary missions?

That depends on how and where the $\Delta V$ is applied. It is usually applied as an impulsive burn in low-Earth orbit. In that case (assuming a circular LEO, $\mu$ is GM, $r$ is distance from Earth center):
$$\Delta V=\sqrt{C_3+{2\mu_{Earth}\over r_{LEO}}} - \sqrt{\mu_{Earth}\over r_{LEO}}$$