# Karman line analog on other celestial bodies Tags: terminology, karman-line - Score: 23 - Views: 2101 - Answers: 4 - Answered: yes - Asked by: user54 - Asked: 2013-09-23 - Edited: 2020-01-28 - Site: space ## Question Is there a common definition of where the space begins on other planets (and other celestial bodies)? An equivalent of the Karman line. How far one should go from the martian surface to get to the outer space? Am I already in space jumping 2 meters above the Moon surface? (please don't answer that anything beyond the earthly Karman line (including any other planets' surfaces) is in space by definition). ## Answers ### Answer by Mark Adler (score: 18) I am not aware of anyone using a Kármán line on another planet, but it's not hard to calculate. I get about 88 km for Mars. The equation is $r\,\rho(r)={2m\over A\,C_L}$, where $r$ is the radius of the Kármán line from the center of the body, $\rho$ is the density as a function of the radius, $m$ is the mass of the aircraft, $A$ is the planform area, and $C_L$ is the coefficient of lift. von Kármán picked some representative values for $m\over A$ and $C_L$, which I don't know. But I don't need to know. I can