The Space Shuttle Discovery left the International Space Station this morning for the last time. To commemorate the ship's accomplishments over 27 years of service, the crew was greeted to a morning wake-up message from Capt. Kirk. "Space, the final frontier," Shatner said in a prerecorded message. "These have been the voyages of the space shuttle Discovery. Her 30-year mission: to seek out new science, to build new outposts, to bring nations together on the final frontier, to boldly go and do what no spacecraft has done before."