chunk: Millions of years later, a Pan Am space plane carries Dr. Heywood Floyd to a space station orbiting Earth for a layover on his trip to Clavius Base, a United States outpost on the moon. After a videophone call with his daughter, Floyd's Soviet scientist friend and her colleague ask about rumors of a mysterious epidemic at Clavius. Floyd declines to answer. At Clavius, Floyd heads a meeting of base personnel, apologizing for the epidemic cover story but stressing secrecy. His mission is to investigate a recently found artifact buried four million years ago. Floyd and others ride in a Moonbus to the artifact, which is a monolith identical to the one encountered by the man-apes. Sunlight strikes the monolith and a loud high-pitched radio signal is heard.