Leaving the Shell Behind

Was Antoine de Saint-Exupéry into esoteric knowledge? 

In chapters 25 and 26 of Le Petit Prince, he talks about needing to leave his shell behind exactly on the anniversary of his landing on the planet Earth in order for him to go back to the asteroid where he came from.

Here is a NASA article that talks about how asteroids carry the precursor to human life.

Did Exupéry believe that we were star seeds?

And why does the little prince say that he has to do it on the anniversary of his arrival?

Recently, I heard this astrologer say that people usually die near their birthday, their arrival on this planet!

Do people leave behind their shells around the same time that they arrive on this planet?

Maybe the next time I visit a cemetery, I'm gonna check if it's true. 

This was one of the saddest parts of the book and I cried while translating it.