One of my earliest contacts with the concept of orbital mechanics was learning about the four cosmic velocities. They were in my primary school handbook. They were referenced in amateur astronomer's guidebook. They appeared during the university lectures. I believe they appeared in some sci-fi novels from the eastern bloc. They are the "daily bread" to anyone interested in space exploration around here.
- First cosmic velocity is the minimal velocity to orbit the planet.
- Second cosmic velocity is the minimal velocity to escape the planet's gravitational influence.
- Third cosmic velocity is the minimum to escape the planet's solar system.
- Fourth cosmic velocity is the minimum to escape the galaxy.
(and it was a bit of a pain to find any - even as simple and crude as the linked one - English language reference to these.)
The Wikipedia article is only available in Russian, Belarussian, French, Polish, Armenian and Bulgarian. And I've never seen anyone on this site ever mention "first cosmic velocity".
Is there any specific reason why this set of terms, so common and fundamental in the former eastern bloc is absolutely nonexistent in the western space exploration community?