Escape velocity is actually the same in any direction, not just directly upward. This is true because in a two-body system, whether or not a trajectory escapes

Escape velocity is actually the same in any direction, not just directly upward. This is true because in a two-body system, whether or not a trajectory escapes to infinity depends only on whether the sign of specific orbital energy[1] is positive or negative. Specific orbital energy is a function of kinetic energy and potential energy, but is independent of the direction of motion. [1]: https://en.wikipedia.org/wiki/Specific_orbital_energy https://en.wikipedia.org/wiki/Specific_orbital_energy