From Space Oddity, of David Bowie(Is there anyone who's not familiar with this song??), I quote :

Though i'm past one hundred thousand miles i'm feeling very still, and I think my spaceship knows which way to go...

I think this part of the song is vary sad.

Yes, Major Tom is very brave, and loves being an astronaut. He is not afraid of being distant from Earth. He feels natural in space. However, he doesn't even know if he's on the right direction... Maybe he's getting away from earth, maybe he lost his track. He can only assume, hope, his spaceship knows which way to go.
I find it sad because Major Tom has to be lonely up in space, without knowing which way he goes. He can't really change things, but rather hope for best.

I believe, we are all Major Tom sometimes...

Sometimes in life, we undergo so many hardships. We don't necessarily know which way we're going, nor do we always have the ability to change things. However, we can hope! We can endure those hardships and thrive... and prosper.
Be brave, let not the fear nor the unknown frighten you.

"You have really made the grade..."
You're great !