So I have a thought that has been haunting me for days (courtesy of something I saw on Reddit):
Is it possible that the crash at the beginning of the film was a flashback to Cooper training for the Lazarus missions 10+ years prior? That would make Professor Brand's comment to Cooper at NASA (i.e., "this is the mission that you were trained for") make even more sense. Not only was Cooper piloting a Ranger with a robot during the crash, it would seem that Rangers were also the primary vehicles used in the Lazarus missions (given Dr. Mann's secondhand knowledge of how to pilot a Ranger).
The Lazarus missions were LAUNCHED ten years ago, but training would've begun much longer before that. Years before, even. Tom was 15 when the movie started, which means he could've not been born during the crash. Hell, "This is the mission you were trained for" could mean just about anything.
COOPER: None of them had family?
BRAND: No attachments. My father insisted.
At the time of the crash, Cooper had Donald and Tom. Murph may or may not have been born, and his wife was likely still alive. Ergo, automatically disqualified from Lazarus because of a family.
That's a very interesting thought, but I don't know about it. It sounds cool and it's intruiging, but how come Cooper never says that was the case? Unless NASA didn't tell him they were training him for the mission. Maybe had he never crashed they would have kept training and came to him with the Lazarus mission at the end