Old Earth late Industrial Age scientist; an advocate for space exploration and pioneered the field of xenology as a true field of science. He was the namesake for both the interplanetary era probe to Delta Pavonis and the interstellar era probe to Xi Geminorum. Also named after him are Sagan Algae, gengineered aeroalgae (i.e. Sky Algae) that are key components in many terraforming strategies.
He has the distinction of having close to three dozen worlds in the Inner Sphere alone named after him, many of them host to dazzling complex ecosystems of terragen design.