Professor Carter reveals he is a member of a secret organisation set up to study the alien signal. He informs the crew that their mission is to travel to Jupiter, where the signal originates, and where all contact with four unmanned probes has been lost. During training on the Lunar surface, Chipper becomes separated from the rest of the crew and hears the music and voices again. The Space Force blasts off for a three year return trip to Jupiter. The ship is hit by a small asteroid, and Chipper begins showing signs of mental impairment, due to the long voyage. The crew encounter one of the unmanned probes and discover that all its electrical equipment has been removed. Chipper again hears the music and voices. The Space Force approaches Jupiter orbit and suffers a complete systems failure.
