Jack Doughty Apr 5, 2014:

Withdrawing my answer In the text I am translating, they use the term отлётная траектория, which I now think is departure trajectory, and also the term орбита перелёта, which I shall translate as escape orbit.

the_val Apr 4, 2014:

departure trajectory versus escape orbit The difference, I think, is that - escape orbit - we are still on that orbit but without speeding-up for leaving it; departure trajectory - we are leaving an escape orbit by departure trajectory. May be, may be :))