Discovery 2 was the uncompleted unseen counterpart of the Discovery 1. It was intended to be used in order to retrieve and return the two austronauts David Bowman and Frank Poole, from Discovery 1 back to Earth. The other three members of the original Discovery mission, were to remain and study Jupiter and TMA-2. But due to complications initiated by the Discovery 1's computer HAL 9000, the entire crew of the ship went dead or missing. With this lack of immediate need to complete the ship, the ship went uncompleted for nine more years, until being replaced by the already built Cosmonaut Alexei Leonov, created by the Soviet Union.