Escape Velocity for Moon: Is the Equation Wrong?

eurekameh · Feb 5, 2013

v,escape = (2*mu/r)^(1/2), where mu = G*M. What I'm asking is if this page is wrong about calculating the escape velocity for the moon. They seem to have the equation wrong (missing 2 in front of mu = G*M,moon).

Table 8.2: Approximate Astrometric Data for the Planets, listing body, symbol, average radius in km, and mu in km^3/sec^2 for Sun, Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, followed by escape velocity and circular orbit formulas for the Moon.

gneill · Feb 5, 2013

If you study the text closely you'll see that they're calculating the orbital speed for a circular orbit just above the Moon's surface, not the escape speed. Multiply by root two to get the escape speed.

eurekameh · Feb 5, 2013

Ah, somehow missed it. Thanks.

Escape Velocity for Moon: Is the Equation Wrong?

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