You would think plunging into deep space, to the outer banks of our solar system, would be a person's career ascension.But for Alan Stern, principal investigator of the New Horizons mission that explored Pluto and more recently the Kuiper Belt, he also recently descended in a deep sea submersible to view the sunken remains of the RMS Titanic.A luxury steamship, the Titanic sank on April 15, 1912 off the coast of Newfoundland in the North Atlantic. Its sinking came after the ship ran into an iceberg during its maiden cruise.