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Assume a spherical planet with mass $M$ and surface radius $r$. The '''standard gravitational parameter''' $\mu$ is the product of the gravitational constant $G$ and $M$ : $\mu = G M $  Assume a spherical planet with mass $M$ and surface radius $r$. The '''standard gravitational parameter''' $$\mu$$ is the product of the gravitational constant $G$ and $M$ : $\mu = G M $ 
E < μ÷r
Climbing out of a gravity well requires energy.
Assume a spherical planet with mass M and surface radius r. The standard gravitational parameter
\mu
is the product of the gravitational constant G and M : \mu = G M