03:53:38 PM Jul 3rd 2013
(Note: I have not seen After Earth, and am basing my comments on plot summaries available here there and everywhere.) Does this seem like an Adaptation of George R. Dickson's: On Messenger Mountain? Spaceship crash in a hostile environment with a beacon that cannot broadcast through the atmosphere and must be launched from on top of a mountain while fighting an alien. I haven't seen any references to this as an adaptation here or on the other wiki....
01:01:48 PM Jul 4th 2013
I'm pretty sure that is a fairly common summary of science fiction works. There is no Word of God to corroborate the hypothesis, so I doubt it holds true here.