The Alien Riddles

Alien life once existed on Mars, and as SpaceX, NASA, and other modern-day explorers set their sights on the Red Planet with ambitious new missions, it may one day return. This episode is a mashup of episodes from two Science Channel shows: Mars: the Secret Science, S01E03, "Conquering the New Frontier" and How the Universe Works, S05E06, "Life and Death on the Red Planet".