Complex sentence: The "Leonov" eventually performs a rendezvous with the "Discovery", and Hal's creator, Dr. Chandra, on the mission, reactivates the HAL 9000 computer to ascertain the cause of his earlier aberrant behavior.
Split into simpler sentences: The "Leonov" eventually performs a rendezvous with the "Discovery". Mission crewmember and Hal's creator, Dr. Chandra, reactivates the HAL 9000 computer to ascertain the cause of his earlier aberrant behavior.