|Dr. David Yellin|
Dr. David Yellin, from Martian Dreams
After his arrival in the ill-fated first capsule, Yellin, together with Major Greg Duprey and Richard Sherman, went out to explore the mines. It turned bad when Duprey and Sherman got stuck in the mines near Syrtis Major at 10°N 71°E after a cave-in while searching for iron ore for Andrew Carnegie.
Yellin, when meeting the Avatar in Martian Dreams, was unable to free them, because he couldn't get the drill ready without a wrench. Thankfully, the Avatar had one, and freed his companions. Afterwards, Yellin was willing to vouch for entry to Olympus. At the end, he returned to Earth.