Escape Velocity for Moon: Is the Equation Wrong?

[eurekameh]

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).

 

[gneill]

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]

Ah, somehow missed it. Thanks.