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
Planet the latter half of the 20th century of more objects within the Solar System and large objects around other stars, disputes arose over what should constitute a planet. There were particular disagreements over whether an object should be considered a planet if it was part of a distinct population such as a belt, or if it was large enough to generate energy by the thermonuclear fusion of deuterium. A growing number of astronomers argued for Pluto to be declassified as a planet, because many similar objects approaching its size had been found in the same region of the Solar System