Pioneer

The time is 2183. Fifty-six-year-old Saunders Maxwell is a stubborn old space-farer who has spent his entire life in space. He has captained the Moon-Mars shuttle and led exploration missions beyond Mars. When he came to Mars in his forties he helped discover the water source that made the first American Mars colony possible.
Later he turned to asteroid mining, captaining a small ship and crew of about a half dozen on repeated trips to the asteroid belt, bringing back minerals or even small asteroids so that the Mars colony could harvest them for the needed resources.
Having just returned from one such four year mission, he and his pilot Harry Nickerson are heading back to Mars when, as they fly over the vast slopes of the giant volcano Olympus Mons, Maxwell spots this strange glint below, a glint that is not natural and should not be there.
When they land they discover something entirely unexpected and impossible, the body of man who had disappeared on a distant asteroid almost a half century before. Sanford Addiono had been on one of the first manned missions to the asteroid belt when he and a partner had vanished. Nothing was ever heard from them again. Even more baffling, two later missions to the asteroid from which they had been lost found that it was gone as well, no longer in orbit where it was supposed to be.
Now, 46 years later, Maxwell finds Addiono's body on the surface of Mars. How Addiono had gotten to Mars from a distant now-lost asteroid orbiting beyond Mars–without a spaceship–was a riddle that almost defied an answer.
That riddle was magnified exponentially by what Addiono had brought back with him. Among his effects was a six-fingered robot hand that had clearly been made by some alien civilization, along with a recorder and memo book describing what Addiono had seen.
Here was a mystery that would rock humanity, the first alien contact. And at that moment Saunders Maxwell decides that he is going to be the person to solve that mystery, even if it takes him through hell and back.
Unfortunately, that is exactly where that journey takes him.
Not that it matters. Saunders Maxwell is a typical human, and for humanity, the journey itself is really all that matters.
So now I stand on earthside shore,
And wonder what I am.
I must go out and find my home.
The journey's what I am.
Chorus:
O Pioneer! O Pioneer!
Where do you go from here?
O Pioneer! O Pioneer!
The stars are far too near.
-A folksong of Mars and the Moon