the question is : there are two identical planets of mass M and radius R spaced 6R apart. What is the escape speed of a rocket launched from the mid-point (3R) between two planets? I use the energe conservation law. K1 + Ua1 + Ub1 =K2 + Ua2 + Ub2 = 0 to get the Vi because the rocket is in the middle, the U1 and U2 should be opposite sign, which will cancel out each other. In this case the escape speed should be 0, why that is not true?