Mission to Mars complete the sequence to pass a test, and the crew dispatches a robotic rover to reproduce the completed signal. Following the transmission, an opening appears in the side of the structure, which Jim, Terri, and Luke enter, while Phil remains at the repaired Earth return vehicle with orders to launch, with or without them, at the agreed time. The opening seals behind them, disrupting radio communication with Phil, and a three-dimensional projection of the solar system depicts the planet Mars, covered with water, being struck by a large asteroid and rendered uninhabitable. A recreation of a Martian then reveals that
Solar System icy objects. Astronomers sometimes informally divide this structure into separate regions. The inner Solar System includes the four terrestrial planets and the asteroid belt. The outer Solar System is beyond the asteroids, including the four giant planets. Since the discovery of the Kuiper belt, the outermost parts of the Solar System are considered a distinct region consisting of the objects beyond Neptune. Most of the planets in the Solar System have secondary systems of their own, being orbited by planetary objects called natural satellites, or moons (two of which, Titan and Ganymede, are larger than the planet Mercury), and, in